Disabling minimum window size?

I recently got a PiTFT for my Pi, and it has been working great. The only issue I have with it is that some windows are convinced that they don't want to be any smaller than a certain size; in some cases this is as big as 800x600. Obviously that makes it kind of hard to use on a little TFT, which is why I was wondering if it is possible to disable the minimum size of a window. I am running raspibian with XFCE on a Pi 2, if it matters. Thanks for any help you can provide!