The initial question in this thread:
1) How can I change the colors for the selected cells?
could also be interpreted to mean:
When selecting a cell range, the color of this range changes temporarily to denote the selection. Where are these colors defined?
Mine is a pale grey that is hard to see, and I would like to change it.
I have changed various colors under 'Tools > LibreOffice > Appearance' without much success. I found a posting elsewhere that showed that the transparency of this color could be affected by going to:
Tools > LibreOffice > View
and clicking/changing the 'Selection/Transparency' setting.
Deselecting the 'transparency' checkbox altogether made the color of the selected cells turn to black, and re-selecting transparency and setting it to a lower value made the selection darker, which is progress. Yet, I would like to change it to pale yellow, rather than dark grey.