Default settings and perceived desktop latency in Windows vs. Qt vs. GTK

Default maximum double-click time (i.e. maximum time between clicks that will register as a double-click) on Windows: 500 ms

in Linux programs that use Qt: 400 ms

in Linux programs that use GTK: 250 ms

Raising that to 400 makes GTK programs feel less "heavy" and more responsive.

Increasing the maximum double-click distance from 5 pixels to 10 also helps. It seems like the general rule is that the more precision a GUI requires of the user, the less responsive it will feel.

There are also usability issues with 250 ms/5 px. Users who have slow reaction time, poor coordination, tremor, etc. would probably have trouble with such settings.

I think I'm going to see how far I get submitting an improvement request to the GTK dev team.