I posted an analogous message on the forum (Programming » LCL). Since the problem was not solved I try to post on the correct forum place.
I checked the legend demo but I got black squares instead of the text on the legend (Lazarus 1.2.5 r45573M FPC 2.6.4 i386-win32-win32/win64). See attached image.
The modifications to TAChart (and the demo too, in order to have a legend colorbar) have been merged to 1.2.4:
r44583 TAChart Add event OnDrawLegend to TChart
r44588 TAChart add code to legenddemo to demonstrate the ownerdrawn legend, fix some layout issues.