Dragging Dockable Panels (when floating) back and forth causes obscene panel growth

[AlbertWiersch]

I undocked a TSpTBXDockablePanel and dragged it around across monitors with different DPIs and the panel size kept growing out of control. It looks like the biggest problem occurred when it grew when dragging it from a higher DPI monitor to a lower DPI monitor. Strangely, the first time it moved to a lower DPI monitor it didn't grow but them moving it back to the higher DPI monitor and then back to the lower DPI monitor caused extreme panel size growth. Just try dragging it back and forth from different DPI monitors to see the bizarre behavior.