Duplicates shown when resizing nodes

[tobi18991]

Due to rendering errors, when selecting a node and resizing it, a duplicate is shown. It vanishes only if the diagram is opened again or when zooming in or out of the diagram.

The problem seems to be related with the ui.editor.graph.refresh() function executed inside the VertexHandler.

Furthermore, while changing the label (content) of a node, the old text is shown behind the new text until the change is commited by deselecting the node.

[tobi18991]

Unfortunately, selecting the label of a cell (text inside attack graph node) is not possible. Therefore, some hotfix for this is needed...