* Create multi summary plot from summary plot(s)
* Rearrange multi summary plot properties
* Enable source stepping toolbar for multi summary plot
* Automatically activate new summary plot when creating from data sources -> data vector tree
* Enable global key controls for switching data in summary and multi summary plots
* Update tooltip texts for summary plot toolbar
* Show summary data vectors in project explorer for both summary cases and ensembles.
* Enable Drag to be able to drag'n'drop data vector into future summary plot
* Make sure tree is refreshed on reload/replace operations
* Provide case id and ensemble id in drag/drop object in addition to address
