I use "front" and "dispose" messages to make a subpatch appear on screen. "front" works well. "Dispose" does close the subpatch, but the subpatch object in the master patch also disappear. Is that a normal behavior ?
The help file for thispatcher specifies 'dispose' to close the patcher window. No mention of 'wclose' in either the help or the reference. Not only does a 'dispose' message delete the subpatch object, an undo won't bring the subpatch back (presumably because it was deleted via the message).
So if you haven't saved your master patch before you unwisely sent the (recommended) 'dispose' message to your carefully crafted subpatch, you've just lost everything. And you can't get it back.
This is not trivial - it's exactly the kind of thing that scares people away from Max. And you can find complaints about this particular problem dating back 2 years. I can't think of any excuse for why this hasn't been fixed.
This could be the corrected help file. The dispose message is good for the reference but bad for the help file. People tend to copy from help files which should be encouraged on all levels, the dangerous parts don't need to be there...