LibreOffice Calc Format | Cells… | Background only seems to offer me a small inadequate palette; in fact, I’ve noticed it’s not even the same palette on Windows 7 and Linux (Kubuntu 12.04 + LO 4.3). How do I either add to this palette or choose a custom color?
Did you try > ‘Tools’ > ‘Options’ > ‘LibreOffice’ > ‘Colours’ ?
The tool was enhanced recently.
I have version 5.3.7.2.0+ of LibreOffice, and I have the same problem. Right click on cell, and show “Format Cells …” → Background color. For text is the color chooser more detailed e.g Last used colors or choose any color, but the color chooser for background color is very simple, There are only some predefined colors. As workaround you can use Styles dialog. Steps are: Click on cell you wants to change bg color and press F11 (this shows style dialog), press Properties icon → Cell Appearnce
A closed question of 2014-11 related to V4.3. (then rather fresh) is not the best place to post in 2018-04. Look for more recent posts, read help, read documentation, ask your own specific question.
LibO abides by a rather rapid development strategy. The present “still” development path reached 5.4.6 and will soon be closed with 5.4.7. There will not be a 5.5. sequence then.
(There may be changes to the user interface again in the current “fresh” branch which reached 6.0.3.)