GK104 [GeForce GTX 770]
Broken: eg. 2.74 + 2.75
Short description of error
Movie Clip Editor's Grid and Dopesheet views' grid theme colors can't be set anywhere. I would recommend to link those to their corresponding Dopesheet Editor and Graph Editor grid colors as they are already present.
Exact steps for others to reproduce the error
Screenshot of Movie Clip Editor grids