I'm working on improving the look of the TabContainer for Godot 4.2.1 now. Will update soon.
Viewing post in Pixel UI Theme for Godot comments
I managed to fix it. It's in the version 1.3 download.
The thick bordered thing is probably a PanelContainer?
Alternatively you can easily override the look for a specific control by overriding in Inspector:
Theme Overrides/Styles/Panel, then add a StyleboxTexture and apply the 8x8_ui_elements.png or a color variation as an AtlasTexture, then select the region you want.
Thank you, the overriding worked. I love your theme but I still have problems with the radio buttons(among other icons): the right radio button textures are shown in the PopupMenu of a OptionButton, but the radio button icons are totally blurry, as if the texture filter is not set correctly. But I checked every single setting and explicitly set the filtering but it didn't help.
I have no more ideas left as to how to solve this, I feel like I tried everything. Maybe you have an idea?