The interface of SimPE consists of many movable panels. If I drag them out accidentally, I can't get them back to the original location. In particular: it is not possible to dock a panel to the bottom below /both/ the resource tree and resource list, here are some vertical tabs on the right that don't go back into a tab form once expanded, and take up screen space. Once a panel is moved out, it can be docked, but not returned to a tab form. It is very easy to drag a tab while attempting to activate it.

How do I reset the layout of SimPE without resetting other preferences? Can I lock it?

There's a button that resets the layout, it's a blue circle with a red X, should be at the top in the row of buttons. I use this one if the UI has gone a bit nutty. It shouldn't reset any other settings, just the layout. You may have to fix a couple things after, because it resets to whatever is default.

I think there's also a "reset layout" option in the preferences.

Not sure if you can save the UI settings as a new default (I'd think so, I don't know how, but I'd like to know). I only know how to save the other settings.

Thank you. I see the button now. I didn't find it in the menus, and assumed they would contain a superset of toolbar items.