Editor: issue of handling an Alt + Click combination in the Room Editor

[ivan-mogilko]

This is more of a question than a bug report, because although I know the most straightforward way to fix this, I am not certain if it's a proper one.

I've added a Alt + LMB combination to the Room Editor recently (b4a5886), but I later realized that when Alt is released, the focus goes to the system menu, as a standard window behavior (regardless of whether you made a click or not). Note this does not mean that the system menu opens, it only gets focus, but opens if you press any directional keys. So for most time you may not notice this. But this is not good anyway, and it makes cursor to change to standard "arrow", as focused control have changed.

This may be fixed easily by marking Alt key release as "handled" in a BaseAreasEditorFilter.KeyReleased method.

However, if we do that unconditionally, that will in turn prevent from actually calling a system menu while room editor has any Area mode enabled.

Then, we may handle Alt release in case user made a click while holding it, thus issuing an actual selection command (this fact may be saved and used on Alt release). This seems more suitable.

But there's my doubt: I've made a cursor change to "select" while Alt is held down. If focus still goes to system menu after user decided NOT to click, will this look wrong?

I suppose this is also a question of UI design. How do other applications treat a similar situation?