I have changed the UI colours on the UI & Layout composer. Still, there are dark grey items showing up when one clicks on Manage Layers --> Upload Zone for Cover.
If one changes the UI colours, these buttons should not be an exception. There is a quick fix by using CSS but those who are not CSS skilled will not be able to change this. Furthermore there is a point by being able to change UI colours on the UI & Layout composer tab. This point becomes awkward when one has to change some buttons via CSS when everything around has changed according to our specs on the UI & Layout composer tab.
The attached print screen shows it.
Hope you do this soon!
Thanks for sharing, will be fixed in the next version.