relative position in rectangle doesn't work

[triessner]

I use rectangles with relative positions to show level of a liquid tank. But it does not work, the relative variable (Tankinhalt_Visu) is ignored, and the level keeps constant (as if the value of Tankinhalt_visu would equal zero). In the javascript webvisu it looks like this (the tank is always full) But it should look like this (again the problem with wrong coordinate in grouped objects occurs in the upper picture, like in issue #12: the black lines which symbolize the outer walls are overlapped by the blue rectangle which is too big):