I don't know what kind of window this is, except for this being a window that slides open side to side rather than up and down. I have no idea whether this pool of water is leaking from the outside into the window, or whether this is condensation coming from somewhere else. That said, I don't even know what I need to know in order to start addressing this water buildup. I have scoured on Google and suspect that it could be a caulking or weather stripping issue, but they don't seem to be matching up to the windows I'm dealing with. What information should I be collecting from your experience? Thanks in advance.