I'm happy to have the new version of DOOM + DOOM II because it comes with DOSBox Staging, whose Keymapper has three mouse buttons to assign.

I want to use it with Catacomb 3-D.

The problem I want to solve is that I want to assign the right mouse button to advance, but it doesn't. Can anyone tell me the steps to follow?

I have Reflection HLE and Catacomb GL, but I'm not interested in the other improvements; I just need this.