diff --git a/ChangeLog b/ChangeLog
index d5a9dd2d4af1d61fef5d332e8fc75c0cf11db0b2..49e1f90fabd38934c4626f64128f79b4c2605ea3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+02-FEB-2020: 12.6.4
+
+- Uses mxGraph 4.1.1 beta 4
+- Fixes possible NPE
+
 02-FEB-2020: 12.6.3
 
 - Updates move preview after key events
diff --git a/VERSION b/VERSION
index cabbe6d9ef596ccc31e3a964e85ce2c4f210ecee..e75790e6cd229dd3a52bbbb39e686bb6ae9421aa 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-12.6.3
\ No newline at end of file
+12.6.4
\ No newline at end of file
diff --git a/etc/mxgraph/mxClient.js b/etc/mxgraph/mxClient.js
index 2ce4bb16fa8769c9e083947179359f6d1a171859..29c59938172801a9e53798c07d60e753ac5e687f 100644
--- a/etc/mxgraph/mxClient.js
+++ b/etc/mxgraph/mxClient.js
@@ -1396,7 +1396,7 @@ d&&null!=b.sourceState&&b.sourceState.setCursor(d));else if(mxEvent.isMultiTouch
 this.highlightEnabled&&(l=c.getDropTarget(this.cells,b.getEvent(),g,e));var m=c.getView().getState(l),n=!1;null!=m&&(e||this.isValidDropTarget(l))?(this.target!=l&&(this.target=l,this.setHighlightColor(mxConstants.DROP_TARGET_COLOR)),n=!0):(this.target=null,this.connectOnDrop&&null!=g&&1==this.cells.length&&c.getModel().isVertex(g)&&c.isCellConnectable(g)&&(m=c.getView().getState(g),null!=m&&(g=null==c.getEdgeValidationError(null,this.cell,g)?mxConstants.VALID_COLOR:mxConstants.INVALID_CONNECT_TARGET_COLOR,
 this.setHighlightColor(g),n=!0)));null!=m&&n?this.highlight.highlight(m):this.highlight.hide();null!=this.guide&&this.useGuidesForEvent(b)?(d=this.guide.move(this.bounds,d,f,e),k=!1):d=this.graph.snapDelta(d,this.bounds,!f,!1,!1);null!=this.guide&&k&&this.guide.hide();c.isConstrainedEvent(b.getEvent())&&(Math.abs(d.x)>Math.abs(d.y)?d.y=0:d.x=0);this.checkPreview();if(this.currentDx!=d.x||this.currentDy!=d.y)this.currentDx=d.x,this.currentDy=d.y,this.updatePreview()}this.updateHint(b);this.consumeMouseEvent(mxEvent.MOUSE_MOVE,
 b);mxEvent.consume(b.getEvent())}};mxGraphHandler.prototype.updatePreview=function(a){this.livePreviewUsed&&!a?null!=this.cells&&(this.setHandlesVisibleForCells(this.graph.getSelectionCells(),!1),this.updateLivePreview(this.currentDx,this.currentDy)):this.updatePreviewShape()};
-mxGraphHandler.prototype.updatePreviewShape=function(){null!=this.shape&&(this.shape.bounds=new mxRectangle(Math.round(this.pBounds.x+this.currentDx),Math.round(this.pBounds.y+this.currentDy),this.pBounds.width,this.pBounds.height),this.shape.redraw())};
+mxGraphHandler.prototype.updatePreviewShape=function(){null!=this.shape&&null!=this.pBounds&&(this.shape.bounds=new mxRectangle(Math.round(this.pBounds.x+this.currentDx),Math.round(this.pBounds.y+this.currentDy),this.pBounds.width,this.pBounds.height),this.shape.redraw())};
 mxGraphHandler.prototype.updateLivePreview=function(a,b){if(!this.suspended){var c=[];null!=this.allCells&&this.allCells.visit(mxUtils.bind(this,function(d,e){if(null==this.graph.view.getState(e.cell))e.destroy();else{var f=e.clone();c.push([e,f]);null!=e.shape&&(null==e.shape.originalPointerEvents&&(e.shape.originalPointerEvents=e.shape.pointerEvents),e.shape.pointerEvents=!1,null!=e.text&&(null==e.text.originalPointerEvents&&(e.text.originalPointerEvents=e.text.pointerEvents),e.text.pointerEvents=
 !1));this.graph.model.isVertex(e.cell)&&(e.x+=a,e.y+=b,this.cloning||(e.view.graph.cellRenderer.redraw(e,!0),e.view.invalidate(e.cell),e.invalid=!1,null!=e.control&&null!=e.control.node&&(e.control.node.style.visibility="hidden")))}}));if(0==c.length)this.reset();else{for(var d=this.graph.view.scale,e=0;e<c.length;e++){var f=c[e][0];if(this.graph.model.isEdge(f.cell)){var g=this.graph.getCellGeometry(f.cell),k=[];if(null!=g&&null!=g.points)for(var l=0;l<g.points.length;l++)null!=g.points[l]&&k.push(new mxPoint(g.points[l].x+
 a/d,g.points[l].y+b/d));var g=f.visibleSourceState,l=f.visibleTargetState,m=c[e][1].absolutePoints;null!=g&&this.isCellMoving(g.cell)?f.view.updateFixedTerminalPoint(f,g,!0,this.graph.getConnectionConstraint(f,g,!0)):(g=m[0],f.setAbsoluteTerminalPoint(new mxPoint(g.x+a,g.y+b),!0),g=null);null!=l&&this.isCellMoving(l.cell)?f.view.updateFixedTerminalPoint(f,l,!1,this.graph.getConnectionConstraint(f,l,!1)):(l=m[m.length-1],f.setAbsoluteTerminalPoint(new mxPoint(l.x+a,l.y+b),!1),l=null);f.view.updatePoints(f,
diff --git a/src/main/webapp/cache.manifest b/src/main/webapp/cache.manifest
index f85c5415f0275910f3cd8a7dc4ecff9e540e82dd..bc14baa1a0b34f8f13ee5a0196e5791fc2c9bbc4 100644
--- a/src/main/webapp/cache.manifest
+++ b/src/main/webapp/cache.manifest
@@ -1,7 +1,7 @@
 CACHE MANIFEST
 
 # THIS FILE WAS GENERATED. DO NOT MODIFY!
-# 02/02/2020 02:37 PM
+# 02/02/2020 02:50 PM
 
 app.html
 index.html?offline=1
diff --git a/src/main/webapp/js/app.min.js b/src/main/webapp/js/app.min.js
index a33b2b1dd7f427590e42b3204ea88b0c004bb8ac..b22620c1da1bc0ef9d2e3360d6f81daa09f1b5f8 100644
--- a/src/main/webapp/js/app.min.js
+++ b/src/main/webapp/js/app.min.js
@@ -1540,7 +1540,7 @@ d&&null!=b.sourceState&&b.sourceState.setCursor(d));else if(mxEvent.isMultiTouch
 this.highlightEnabled&&(l=c.getDropTarget(this.cells,b.getEvent(),g,e));var m=c.getView().getState(l),n=!1;null!=m&&(e||this.isValidDropTarget(l))?(this.target!=l&&(this.target=l,this.setHighlightColor(mxConstants.DROP_TARGET_COLOR)),n=!0):(this.target=null,this.connectOnDrop&&null!=g&&1==this.cells.length&&c.getModel().isVertex(g)&&c.isCellConnectable(g)&&(m=c.getView().getState(g),null!=m&&(g=null==c.getEdgeValidationError(null,this.cell,g)?mxConstants.VALID_COLOR:mxConstants.INVALID_CONNECT_TARGET_COLOR,
 this.setHighlightColor(g),n=!0)));null!=m&&n?this.highlight.highlight(m):this.highlight.hide();null!=this.guide&&this.useGuidesForEvent(b)?(d=this.guide.move(this.bounds,d,f,e),k=!1):d=this.graph.snapDelta(d,this.bounds,!f,!1,!1);null!=this.guide&&k&&this.guide.hide();c.isConstrainedEvent(b.getEvent())&&(Math.abs(d.x)>Math.abs(d.y)?d.y=0:d.x=0);this.checkPreview();if(this.currentDx!=d.x||this.currentDy!=d.y)this.currentDx=d.x,this.currentDy=d.y,this.updatePreview()}this.updateHint(b);this.consumeMouseEvent(mxEvent.MOUSE_MOVE,
 b);mxEvent.consume(b.getEvent())}};mxGraphHandler.prototype.updatePreview=function(a){this.livePreviewUsed&&!a?null!=this.cells&&(this.setHandlesVisibleForCells(this.graph.getSelectionCells(),!1),this.updateLivePreview(this.currentDx,this.currentDy)):this.updatePreviewShape()};
-mxGraphHandler.prototype.updatePreviewShape=function(){null!=this.shape&&(this.shape.bounds=new mxRectangle(Math.round(this.pBounds.x+this.currentDx),Math.round(this.pBounds.y+this.currentDy),this.pBounds.width,this.pBounds.height),this.shape.redraw())};
+mxGraphHandler.prototype.updatePreviewShape=function(){null!=this.shape&&null!=this.pBounds&&(this.shape.bounds=new mxRectangle(Math.round(this.pBounds.x+this.currentDx),Math.round(this.pBounds.y+this.currentDy),this.pBounds.width,this.pBounds.height),this.shape.redraw())};
 mxGraphHandler.prototype.updateLivePreview=function(a,b){if(!this.suspended){var c=[];null!=this.allCells&&this.allCells.visit(mxUtils.bind(this,function(d,e){if(null==this.graph.view.getState(e.cell))e.destroy();else{var f=e.clone();c.push([e,f]);null!=e.shape&&(null==e.shape.originalPointerEvents&&(e.shape.originalPointerEvents=e.shape.pointerEvents),e.shape.pointerEvents=!1,null!=e.text&&(null==e.text.originalPointerEvents&&(e.text.originalPointerEvents=e.text.pointerEvents),e.text.pointerEvents=
 !1));this.graph.model.isVertex(e.cell)&&(e.x+=a,e.y+=b,this.cloning||(e.view.graph.cellRenderer.redraw(e,!0),e.view.invalidate(e.cell),e.invalid=!1,null!=e.control&&null!=e.control.node&&(e.control.node.style.visibility="hidden")))}}));if(0==c.length)this.reset();else{for(var d=this.graph.view.scale,e=0;e<c.length;e++){var f=c[e][0];if(this.graph.model.isEdge(f.cell)){var g=this.graph.getCellGeometry(f.cell),k=[];if(null!=g&&null!=g.points)for(var l=0;l<g.points.length;l++)null!=g.points[l]&&k.push(new mxPoint(g.points[l].x+
 a/d,g.points[l].y+b/d));var g=f.visibleSourceState,l=f.visibleTargetState,m=c[e][1].absolutePoints;null!=g&&this.isCellMoving(g.cell)?f.view.updateFixedTerminalPoint(f,g,!0,this.graph.getConnectionConstraint(f,g,!0)):(g=m[0],f.setAbsoluteTerminalPoint(new mxPoint(g.x+a,g.y+b),!0),g=null);null!=l&&this.isCellMoving(l.cell)?f.view.updateFixedTerminalPoint(f,l,!1,this.graph.getConnectionConstraint(f,l,!1)):(l=m[m.length-1],f.setAbsoluteTerminalPoint(new mxPoint(l.x+a,l.y+b),!1),l=null);f.view.updatePoints(f,
@@ -8697,7 +8697,7 @@ ka.style.cssText="margin:0 8px 0 8px;";ka.setAttribute("value","100 %");ka.style
 (this.page=this.ui.currentPage);this.page!=this.ui.currentPage?null!=this.page.viewState&&(this.ignoreColor||(this.page.viewState.background=this.color),this.ignoreImage||(this.page.viewState.backgroundImage=this.image),null!=this.format&&(this.page.viewState.pageFormat=this.format),null!=this.mathEnabled&&(this.page.viewState.mathEnabled=this.mathEnabled),null!=this.shadowVisible&&(this.page.viewState.shadowVisible=this.shadowVisible)):(G.apply(this,arguments),null!=this.mathEnabled&&this.mathEnabled!=
 this.ui.isMathEnabled()&&(this.ui.setMathEnabled(this.mathEnabled),this.mathEnabled=!this.mathEnabled),null!=this.shadowVisible&&this.shadowVisible!=this.ui.editor.graph.shadowVisible&&(this.ui.editor.graph.setShadowVisible(this.shadowVisible),this.shadowVisible=!this.shadowVisible))};Editor.prototype.useCanvasForExport=!1;try{var x=document.createElement("canvas"),C=new Image;C.onload=function(){try{x.getContext("2d").drawImage(C,0,0);var a=x.toDataURL("image/png");Editor.prototype.useCanvasForExport=
 null!=a&&6<a.length}catch(D){}};C.src="data:image/svg+xml;base64,"+btoa(unescape(encodeURIComponent('<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="1px" height="1px" version="1.1"><foreignObject pointer-events="all" width="1" height="1"><div xmlns="http://www.w3.org/1999/xhtml"></div></foreignObject></svg>')))}catch(A){}})();
-(function(){var a=new mxObjectCodec(new ChangePageSetup,["ui","previousColor","previousImage","previousFormat"]);a.beforeDecode=function(a,d,b){b.ui=a.ui;return d};a.afterDecode=function(a,d,b){b.previousColor=b.color;b.previousImage=b.image;b.previousFormat=b.format;null!=b.foldingEnabled&&(b.foldingEnabled=!b.foldingEnabled);null!=b.mathEnabled&&(b.mathEnabled=!b.mathEnabled);null!=b.shadowVisible&&(b.shadowVisible=!b.shadowVisible);return b};mxCodecRegistry.register(a)})();(function(){EditorUi.VERSION="12.6.3";EditorUi.compactUi="atlas"!=uiTheme;mxGraphView.prototype.defaultDarkGridColor="#6e6e6e";"dark"==uiTheme&&(mxGraphView.prototype.gridColor=mxGraphView.prototype.defaultDarkGridColor);EditorUi.enableLogging="1"!=urlParams.stealth&&/.*\.draw\.io$/.test(window.location.hostname)&&"support.draw.io"!=window.location.hostname;EditorUi.drawHost="https://www.draw.io";EditorUi.lastErrorMessage=null;EditorUi.ignoredAnonymizedChars="\n\t`~!@#$%^&*()_+{}|:\"<>?-=[];'./,\n\t";
+(function(){var a=new mxObjectCodec(new ChangePageSetup,["ui","previousColor","previousImage","previousFormat"]);a.beforeDecode=function(a,d,b){b.ui=a.ui;return d};a.afterDecode=function(a,d,b){b.previousColor=b.color;b.previousImage=b.image;b.previousFormat=b.format;null!=b.foldingEnabled&&(b.foldingEnabled=!b.foldingEnabled);null!=b.mathEnabled&&(b.mathEnabled=!b.mathEnabled);null!=b.shadowVisible&&(b.shadowVisible=!b.shadowVisible);return b};mxCodecRegistry.register(a)})();(function(){EditorUi.VERSION="12.6.4";EditorUi.compactUi="atlas"!=uiTheme;mxGraphView.prototype.defaultDarkGridColor="#6e6e6e";"dark"==uiTheme&&(mxGraphView.prototype.gridColor=mxGraphView.prototype.defaultDarkGridColor);EditorUi.enableLogging="1"!=urlParams.stealth&&/.*\.draw\.io$/.test(window.location.hostname)&&"support.draw.io"!=window.location.hostname;EditorUi.drawHost="https://www.draw.io";EditorUi.lastErrorMessage=null;EditorUi.ignoredAnonymizedChars="\n\t`~!@#$%^&*()_+{}|:\"<>?-=[];'./,\n\t";
 EditorUi.templateFile=TEMPLATE_PATH+"/index.xml";EditorUi.cacheUrl="1"==urlParams.dev?"/cache":window.REALTIME_URL;null==EditorUi.cacheUrl&&"undefined"!==typeof DrawioFile&&(DrawioFile.SYNC="none");Editor.cacheTimeout=1E4;EditorUi.enablePlantUml=EditorUi.enableLogging;EditorUi.isElectronApp=null!=window&&null!=window.process&&null!=window.process.versions&&null!=window.process.versions.electron;EditorUi.scratchpadHelpLink="https://desk.draw.io/support/solutions/articles/16000042367";EditorUi.logError=
 function(a,b,c,d,f){if("1"==urlParams.dev)EditorUi.debug("logError",a,b,c,d,f);else if(EditorUi.enableLogging)try{if(a!=EditorUi.lastErrorMessage&&(null==a||null==b||-1==a.indexOf("Script error")&&-1==a.indexOf("extension"))&&null!=a&&0>a.indexOf("DocumentClosedError")){EditorUi.lastErrorMessage=a;var e=0<=a.indexOf("NetworkError")||0<=a.indexOf("SecurityError")||0<=a.indexOf("NS_ERROR_FAILURE")||0<=a.indexOf("out of memory")?"CONFIG":"SEVERE",m=null!=window.DRAWIO_LOG_URL?window.DRAWIO_LOG_URL:"";
 f=null!=f?f:Error(a);(new Image).src=m+"/log?severity="+e+"&v="+encodeURIComponent(EditorUi.VERSION)+"&msg=clientError:"+encodeURIComponent(a)+":url:"+encodeURIComponent(window.location.href)+":lnum:"+encodeURIComponent(c)+(null!=d?":colno:"+encodeURIComponent(d):"")+(null!=f&&null!=f.stack?"&stack="+encodeURIComponent(f.stack):"")}}catch(z){}};EditorUi.logEvent=function(a){if("1"==urlParams.dev)EditorUi.debug("logEvent",a);else if(EditorUi.enableLogging)try{var b=null!=window.DRAWIO_LOG_URL?window.DRAWIO_LOG_URL:
diff --git a/src/main/webapp/js/viewer.min.js b/src/main/webapp/js/viewer.min.js
index a2129b0147198b1fd9ba07461d9217162d9efcc6..2cb8159fe473ef9d62b4ed6929ae406231007146 100644
--- a/src/main/webapp/js/viewer.min.js
+++ b/src/main/webapp/js/viewer.min.js
@@ -1505,7 +1505,7 @@ d&&null!=b.sourceState&&b.sourceState.setCursor(d));else if(mxEvent.isMultiTouch
 this.highlightEnabled&&(l=c.getDropTarget(this.cells,b.getEvent(),g,e));var m=c.getView().getState(l),n=!1;null!=m&&(e||this.isValidDropTarget(l))?(this.target!=l&&(this.target=l,this.setHighlightColor(mxConstants.DROP_TARGET_COLOR)),n=!0):(this.target=null,this.connectOnDrop&&null!=g&&1==this.cells.length&&c.getModel().isVertex(g)&&c.isCellConnectable(g)&&(m=c.getView().getState(g),null!=m&&(g=null==c.getEdgeValidationError(null,this.cell,g)?mxConstants.VALID_COLOR:mxConstants.INVALID_CONNECT_TARGET_COLOR,
 this.setHighlightColor(g),n=!0)));null!=m&&n?this.highlight.highlight(m):this.highlight.hide();null!=this.guide&&this.useGuidesForEvent(b)?(d=this.guide.move(this.bounds,d,f,e),k=!1):d=this.graph.snapDelta(d,this.bounds,!f,!1,!1);null!=this.guide&&k&&this.guide.hide();c.isConstrainedEvent(b.getEvent())&&(Math.abs(d.x)>Math.abs(d.y)?d.y=0:d.x=0);this.checkPreview();if(this.currentDx!=d.x||this.currentDy!=d.y)this.currentDx=d.x,this.currentDy=d.y,this.updatePreview()}this.updateHint(b);this.consumeMouseEvent(mxEvent.MOUSE_MOVE,
 b);mxEvent.consume(b.getEvent())}};mxGraphHandler.prototype.updatePreview=function(a){this.livePreviewUsed&&!a?null!=this.cells&&(this.setHandlesVisibleForCells(this.graph.getSelectionCells(),!1),this.updateLivePreview(this.currentDx,this.currentDy)):this.updatePreviewShape()};
-mxGraphHandler.prototype.updatePreviewShape=function(){null!=this.shape&&(this.shape.bounds=new mxRectangle(Math.round(this.pBounds.x+this.currentDx),Math.round(this.pBounds.y+this.currentDy),this.pBounds.width,this.pBounds.height),this.shape.redraw())};
+mxGraphHandler.prototype.updatePreviewShape=function(){null!=this.shape&&null!=this.pBounds&&(this.shape.bounds=new mxRectangle(Math.round(this.pBounds.x+this.currentDx),Math.round(this.pBounds.y+this.currentDy),this.pBounds.width,this.pBounds.height),this.shape.redraw())};
 mxGraphHandler.prototype.updateLivePreview=function(a,b){if(!this.suspended){var c=[];null!=this.allCells&&this.allCells.visit(mxUtils.bind(this,function(d,e){if(null==this.graph.view.getState(e.cell))e.destroy();else{var f=e.clone();c.push([e,f]);null!=e.shape&&(null==e.shape.originalPointerEvents&&(e.shape.originalPointerEvents=e.shape.pointerEvents),e.shape.pointerEvents=!1,null!=e.text&&(null==e.text.originalPointerEvents&&(e.text.originalPointerEvents=e.text.pointerEvents),e.text.pointerEvents=
 !1));this.graph.model.isVertex(e.cell)&&(e.x+=a,e.y+=b,this.cloning||(e.view.graph.cellRenderer.redraw(e,!0),e.view.invalidate(e.cell),e.invalid=!1,null!=e.control&&null!=e.control.node&&(e.control.node.style.visibility="hidden")))}}));if(0==c.length)this.reset();else{for(var d=this.graph.view.scale,e=0;e<c.length;e++){var f=c[e][0];if(this.graph.model.isEdge(f.cell)){var g=this.graph.getCellGeometry(f.cell),k=[];if(null!=g&&null!=g.points)for(var l=0;l<g.points.length;l++)null!=g.points[l]&&k.push(new mxPoint(g.points[l].x+
 a/d,g.points[l].y+b/d));var g=f.visibleSourceState,l=f.visibleTargetState,m=c[e][1].absolutePoints;null!=g&&this.isCellMoving(g.cell)?f.view.updateFixedTerminalPoint(f,g,!0,this.graph.getConnectionConstraint(f,g,!0)):(g=m[0],f.setAbsoluteTerminalPoint(new mxPoint(g.x+a,g.y+b),!0),g=null);null!=l&&this.isCellMoving(l.cell)?f.view.updateFixedTerminalPoint(f,l,!1,this.graph.getConnectionConstraint(f,l,!1)):(l=m[m.length-1],f.setAbsoluteTerminalPoint(new mxPoint(l.x+a,l.y+b),!1),l=null);f.view.updatePoints(f,
diff --git a/src/main/webapp/service-worker.js b/src/main/webapp/service-worker.js
index 4dddbd04c05a953c324fe460438af1e31ca8d85c..bb3cb72d88e0c0018c3371701e6c67a926fe1ac7 100644
--- a/src/main/webapp/service-worker.js
+++ b/src/main/webapp/service-worker.js
@@ -6,7 +6,7 @@ if (workbox)
 	workbox.precaching.precacheAndRoute([
   {
     "url": "js/app.min.js",
-    "revision": "0bc6d325a00a8b17599888b78f240e69"
+    "revision": "dc34476c8a993b60a793ba1a084b9d56"
   },
   {
     "url": "index.html",