I have installed
qt5ct to apply gtk2 theme on Qt apps (by default they follow the Fusion theme). However, Qt apps (I have tried GNU Octave and Brightness Controller) are taking too much time to start up when the gtk2 theme is enabled.
For example, Brightness Controller is taking ~25 seconds to load in gtk2 theme in qt5ct, while it takes 1-2 seconds to load under Fusion or any other theme (I have measured this by looking at a watch after clicking the icon).
The same goes for GNU Octave.
How to fix this? Please let me know whether I need to post any logs.
qt5ct itself is also very slow to load.
I have used
qt5ct before in previous versions of Xubuntu, and there it was much faster.