I just stumbled across the (now?) missing feature to send a frame to back or bring it to front. When is this supposed to come or return?
In particular with nested frames, colored frames help a lot to easily identify boundaries between frames. Yet if one creates a surrounding frame after the nested frames the surrounding frame is always on top the nested ones and its color hides the colors of the nested frames. The only workaround seems to duplicate each nested frame so that they are created after the surrounding frame and are thus now on top the surrounding frame, then rename all of them and delete the original ones. Which is cumbersome and a waste of time.