Operating system: Linux-4.4.0-146-generic-x86_64-with-debian-stretch-sid 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 418.56
Broken: version: 2.80 (sub 71), branch: master, commit date: 2019-05-23 04:27, hash: rBf417a717b1d9
Short description of error
If you want to colorized multiple tracking markers, in order to better visually separate them (for example when using them as reference points in the 3d viewport), and press the button "Copy color to all selected tracks", the colors are updated in the MCE, but not in the 3d viewport. Only if you disable and enable the "Use color" checkbox, the colors update. Probably some UI update trigger missing. Actually, there are quite a few places in the MCE, where python driven operators do not trigger an immediate update of UI items, but that's maybe for a different bug report :)
Exact steps for others to reproduce the error
Open the attached blendfile and click the button with this operator bpy.ops.clip.track_copy_color()
The colors update in MCE but not in viewport.