I use vim a lot, and start and stop a lot of instances, rather than working with one instance with multiple tabs or viewports. I noticed a half-second delay since release upgrading every time I started gvim. Now, I set a 200 ms blink to my cursor because the normal 1 s blink is just too slow, so it was very annoying.
Using vim's --startuptime feature, I saw that vim was stalling for 600 ms "starting GUI". This didn't happen on eoan, and affected every version I tried, the stock one from the repositories, the eoan version, and the one I build from git. This occurred even when booted from the focal iso, running the eoan executable. The Ubuntu and Xubuntu isos also do not have this delay.
Today I stumbled on a mitigation. In Kubuntu the default GTK2 and GTK3 themes are called "Breeze". Vim's use of themed GUI elements is minimal, especially with the menu and tool bar turned off as most users do, so I don't pay much attention to it. But changing the GTK3 theme away from "Breeze" or "Breeze-dark" reduces the delay from 600 ms to about 200, depending on the theme.
I never liked the Breeze themes anyway. They seem to work very hard to make KDE look like an iPad
The rest of the vim start up, sourcing over 60 scripts, takes less than 100 ms. Crazy.
IMO either the Breeze GTK3 theme should fixed, or Kubuntu should default to something else.
Using vim's --startuptime feature, I saw that vim was stalling for 600 ms "starting GUI". This didn't happen on eoan, and affected every version I tried, the stock one from the repositories, the eoan version, and the one I build from git. This occurred even when booted from the focal iso, running the eoan executable. The Ubuntu and Xubuntu isos also do not have this delay.
Today I stumbled on a mitigation. In Kubuntu the default GTK2 and GTK3 themes are called "Breeze". Vim's use of themed GUI elements is minimal, especially with the menu and tool bar turned off as most users do, so I don't pay much attention to it. But changing the GTK3 theme away from "Breeze" or "Breeze-dark" reduces the delay from 600 ms to about 200, depending on the theme.
I never liked the Breeze themes anyway. They seem to work very hard to make KDE look like an iPad
The rest of the vim start up, sourcing over 60 scripts, takes less than 100 ms. Crazy.
IMO either the Breeze GTK3 theme should fixed, or Kubuntu should default to something else.