Periodic NullPtrException when relocating dock panes

[jdall]

On my Ubuntu 12.04 workstation with 3 monitors running Gnome Classic and on my laptop running SolydX 8, I'm from time to time getting an NullPtrException when relocating dock panes.

The exception is thrown in line 166 of org.dockfx.DockNodeTitleBar due to the stage variable being null. My workaround is a surrounding "if (stage != null) {" but that's maybe/probably not the right fix (I've only a few hours experience with DockFX).

FYI: I've not seen the same issue when testing the clearcontrol fork on the laptop, but unfortunately relocating dock panes is just not working on the ubuntu 12.04 workstation. Only the hkmoon fork does the trick (I've tested all forks which has been recently updated).
It's a bit annoying that starting to drag a pane relocates it to the center of the window in floating mode, and then one has to move the mouse to the pane and click and drag it into the wanted position.
But it's still far better than the other forks that does not work at all.