How to set pane size when docking?

[Lianyang]

At present, I can use "PaneStateChange" to set the size of floating window, or "ReatinPaneSizeMode" to keep floating size same with previous docking size. 

My question is that if I dock the floating window back, how can I set the docking size instead of the default stretching along the horizontal or vertical direction.

Or is there any parameter to indicate the docking process finished so that I can reset the pane size after docking.

 

Thanks

Lianyang