It would be nice to be able to click the mouse to take the position but I think that might be too complicated for me since the active window is changed to where the cursor is and my window no longer sees the mouse.
First, I need to disclaim that I don't know how to do what I'm going to suggest using the Lazarus framework but, you can have a thread that is mostly a loop executing GetCursorPos followed by Sleep(20) that sends the mouse coordinates to any window you want. I said "mostly" because you probably should have a mechanism in place to end the thread once you no longer need it.
If you'd rather not use a thread, you can also do it in a WM_TIMER message. Personally, I prefer a thread because WM_TIMER messages can be erratic at times.
Maybe someone knowledgeable in using the framework can show you how it's done with a TIMER (it probably only takes a few lines of code.) that is, if you are interested in such a solution.
HTH.