There are two included subcompositions. One saves the window position, while the other saves the window position and window size. My original composition for capturing window position and size didn't correctly check if the file existed first, but this revised composition does.
Run the composition and change the window position or size. When the composition is started again, the window will open at the same position, with the same dimensions.
Currently Render Window nodes run at c.60 FPS. For some things we may want to run at a high frame rate. It would be great to have a menu that would allow us to select the FPS of the renders. We may want a UI to use less processing power, and other times we may want to run at 120FPS. Also there may be situation where we want to use 75FPS to sync with projects etc.