[Qt] FocusChanged changes

[Paul Ishenin]

zeljko wrote:
> I think it's because of workspace (it manages children windows) 
> (Application<->MainForm<->Workspace<->MDIChild<->).
> I know that my patch is workaround, but as I can see it breaks nothing,
> MDIChilds are focused properly ... (workspace is doing this).
> As you said before, problem is in missing LCL implementation, so we can sign 
> it as workaround until better times for MDI comes :)
>
> Shoud I commit ?
>   
yes.