Currently both Glass and Prism leak OpenGL resources (textures and/or FBOs). The double_buffering.patch from RT-26702 fixes the leak in Glass, but resources are still leaked.

The problem could be reproduced with the HelloWindowAbuse from rt-closed/toys. This app rapidly creates and destroys windows. On my system I can run up to 1000 windows which is followed by system-wide freezes.

On the Mac OS X the following tools could be used to identify that these are leaks:
1. OpenGL profiler could calculate how many times we call genFBO/genTextures and deleteFBO/deleteTextures. It appears that during the HellowWindowAbuse run we allocate around 20% more resources than free.
2. OpenGL Driver Monitor is able to track the number of textures currently allocated by the program. It shows the constant increase in this number. On my machine this tool is quite buggy, because sometimes it shows that we free more textures than allocate, so the number goes below zero. I am not sure is this is a bug in the tool or if this is due to some problems in FX code.

These tools could be downloaded from the Apple's web site in Graphics Tools pack.

The problem was found on Mac OS X 10.7.5 and 10.8.3, other platforms were not tested.