70b956ba53
The issue was that the tooltip function arguments were sometimes allocated but
not freed. The solution is to handle the lifetime of the argument better. The
code now makes a copy of the argument when it's passed to a layout function. In
an idea world, one could just use something like `std::function` instead of
manual memory management, but the API does not support it yet.
This was caused by f3a1d8fad5.
Pull Request: https://projects.blender.org/blender/blender/pulls/143043