Yes, sorry, I made both the comments and the patch too hastily and agree that it should not be removed based on my findings.
It should be noted though that wx3 or GTK3 by themselves is not to blame here, I'm guessing it should affect wx2 and GTK2 too because it's more of a logical problem in where a user created the server node in a light theme which will save a white color for the background... then if the user switches to a dark theme, the saved white color is problematic.
I noticed work on pgadmin4 too and while interesting, I want to see pgadmin3 shine on linux desktops in the life it has left which might be quite some time (?). I see several distinct areas of work that I'd like to contribute efforts with:
1. Upgrade to latest stable wx
2. Compile with GTK+ 3.x as default on Linux (not sure it's ready for this, needs research and collaboration with dist packaging)
3. Evaluate which controls that can/need replacement (i.e replace with wxTreeListCtrl, wxDataViewCtrl and perhaps wxToolBar)
4. Refactor existing code to use the controls that pass evaulation
Feedback and guidance on how to proceed is much appreciated!
/Björn