Hello, It has been only a few weeks since I first started learning Chimera 1.14 (build 42094) on a Linux64 system with X11. I hope my experiences will help you improve both Chimera and ChimeraX. Earlier today, I reported a situation which results in an unexpected handling of a "divide by zero" bug. I am using the experience to also learn some Python. I am sure there are better ways, but I edited your playmorph.py code to record an animation with a morphing sequence played in reverse. I admit that I still do not understand the different coordinate systems used in Chimera. I have a question which can simply be answered using a ruler, but I am hoping there is another more elegant solution. "2D Labels" arrow ends are specified as a percentage of the screen width and screen height (range 0.0 to 1.0). I would like to draw an arrow whose end (x,y) is specified with precision. After I can specify the windowsize Is there a way to request the "window-screen" coordinates of a specific atom-spec? This is useful, because if I have set the windowsize then I can simply divide the coordinates by the window dimensions to get the desired end for the arrow. Many thanks, Stephen