#31 Toolbar icons: focus first, close if clicked twice.

[Dr.Beco]

When clicking on toolbar icons such as:

• DB switcher
• Game list
• PGN
• ECO
• Tree
• Engine

If the window is already open (docked at right panel), it would be nice if before close, the first click could bring it to front, giving it focus. If clicked again, then close.

That would prevent closing docks you don't want to, and add another way to visualize the window with less mouse movement, improving usability. Thanks a lot.