ToolWindow->Close() and ToolWindow->Activate();

Maybe we're using the Tool window faulty but we have a strange behaviour.
When closing a toolwindow, the extra size gets put on both the window below the closing toolwindow and the one above, but when opening, it takes space from the toolwindow above only, thus making the lower window bigger and bigger each time you open and close the window.


E.g when we have visual appearance for toolWindows like:
ToolWindow1
ToolWindow2
ToolWindow3

If we use ToolWindow2->Close and then activate the height of ToolWindow1 is decreased and the height of ToolWindow3 is increased.

In our case we have the ToolWindow2 that shall be opened closed many times and after a few times the tool looks very strange.

How can we avoid this kind of behaviour, some kind of property?

Br,
Cecilia