I think the viewer pane needs a "lock" checkbox builtin in its little toolbar. When you change layout/toolbars around or resize meta or file displays to get the viewer pane how you want it, my button with the "viewer pane lock" command is always not there. It's a crucial feature for the viewer pane, it should be right in the toolbar. Being a native feature would also make it more popular and more easy to access for regular users. I estimate that only 1% of people know about the lock feature and 0.01% created a hotkey/button to actually lock the pane. o)
Sticking to existing concepts and making the viewer pane toolbar customizable like the path bar or the viewer bar or any other toolbar would make sense as well.. I could add that button myself right there.. o)
Might make sense as an option, off by default. We found with the similar lock in the Folder Tree titlebar that people constantly click it without knowing what it does, and then wonder why the tree is "broken" afterwards.
Making the little viewer pane buttons configurable would definitely be nice, as there are so many of them already. Same with the context menu, where both are editable in the standalone viewer but not the viewer pane (yet).
