Re: [platform-swt-dev] SWT/GTK and Gnome Summit

[Seth Nickell <snickell@xxxxxxxxxxxx>]

> Another problem is overlapping and z-order.  Overlapping widgets are very 
> common in Eclipse.  Several Eclipse UI features are implemented by 
> shuffling the z-order of things (e.g., switching perspectives). Obviously, 
> this is not the UI style GTK creators had in mind.  Widgets in a typical 
> GTK app never overlap.  GTK does not provide facilities to directly 
> control the z-order.  We solve this by having an X window with every 
> widget's "top handle", and calling X directly to control the z-order.

This causes a major problem, namely the flashing and screen redraw
problems Eclipse experiences when you switch perspectives, move tool
panes, etc (at least, I believe this is where the problem lies after
hunting for a couple hours). GTK2 is double buffered, very important to
perceptions of speed and how "comfortable" software is to use, and
manually tweaking the z-order blows that to hell.

I used the Windows version of Eclipse for the first time a couple days
ago, and the difference blew me away. The Windows version came across as
much more polished and visually smooth. Initially I thought it was a
performance issue (Win32 JDK/JIT tends to be faster), but after poking
around a bit I realized it was largely the crazy redraw problems
(problems that would basically disappear with double buffering).

-Seth