Version 2.7.8 (not listed) for Mac
Issue with setting display colours via menu kstars->Preference->Colors

If colours are modified they are often (normally) not saved, even if Save "Current Colors ..." is used to create a new colour scheme.

e.g. Through preferences set opaque horizon and position so horizon visible in sky chart. In colours "tab" select default colours scheme and then "Save Current Colors ..." and create a new scheme. Make sure new colour scheme selected. To left colour list select e.g. Horizon and change colour to e.g. R(32), G(64), B(32). Displayed horizon colour will change (as expected). (Close preferences and go back in at this point makes no difference). Click on default Colour scheme (and horizon displayed will change to default colour scheme (as expected). Click back on the Test colour scheme and horizon stays at original colour (from Default colour scheme) NOT as previously set (i.e. NOT to R(32), G(64), B(32)).

My own investigations: If I set e.g. Horizon colour to R(1) G(2) B(3) and immediately save colour scheme to new scheme (e.g. test1) then the colour written to test1.color for the horizon is correct. But if I select e.g Default Colour scheme then select back to test1, test 1 now shows the Default scheme horizon and clicking to set the horizon colour is initially the Default scheme RGB values. But exit and restart Kstars and the test1 scheme works properly (as saved in the file, Horizon at R(1) G(2) B(3).

1. It looks like the settings in <scheme name>.color are correct but the app is not selecting or setting them correctly when switching between profiles.

Additional more minor related issues
a. When you select a colour scheme, OK, exit kstars, menus Preferences->colors no scheme is highlighted (even though the coloyrs being used are for the correct scheme when you exited.

b. colors.dat often gets "out-of-step" with the schemes. Sign that this has happened is when you select a scheme in preferences but "Remove Color Scheme" is greyed out/disabled. e.g. the scheme was previously deleted but the entry for the scheme was not removed from colors.dat. I have also observed a case where a listed scheme (that had not been deleted and had a .color file could not be deleted as the Remove Color Scheme button was disabled when the profile was selected (i.e. scheme was properly listed in colors.dat as well as having .color file)

c. When you have a scheme selected and you make a change to a colour element e.g. Horizon the sky chart changes the colour but the updated colour is not written back to the scheme file and thus on switching scheme or exiting/restarting the change is lost. To save the change you must save the scheme as a new names scheme (you cannot overwrite an existing scheme).

There may be other issues but it gets very difficult to be completely repeatable when observed issues might be caused by other already listed issues (above).

Sorry it's a complex explanation. If you can't make muh sense of can't reproduce the issues then do ask for a better explanation.