Create a lister with multiple open folder tabs and save it as a layout. Delete a folder that is one of the layout tabs. Close the lister. Open the layout. Deleted folder tab appears. Can close the tab, but can't do other things like add files, etc., and folder reappears whenever layout is opened anew. Expected behavior: tab for deleted folder would not appear anymore in layout.
Did you try to re-save the layout after the change? If the folder keeps coming back, that's how it is supposed to work.
I know that manual maintenance of the layout along with folder management works, it's just that I wouldn't expect to have to do that--I'd expect that "smarts" to be built-in to the program in some way. Using the product is good, tinkering with it is bad.
Layouts stay as you saved them.
Consider someone who didn't delete the folder on purpose, or did but was going to recreate it again in a moment. They would not want all their layouts to forget their folder tabs pointing at it. Or they may want the tabs but to point them at a new folder, which we have no way of predicting.
"Consider someone who didn't delete the folder on purpose": Yet the layout would not act as a warning that the folder had been inadvertently deleted, so the user doesn't find out as soon as they could that "uh oh, a folder is missing!". Basically, the fantom tab is lying to the user: a folder tab is open, but there is no folder: it's a fantom. Now the user needs to know the concept of "fantom tab"--not good. If the user tries to use the fantom tab, say by trying to create a file in it, THEN they will receive an error dialog: "An error occurred creating a new file of type '.txt': The system cannot find the path specified. (3)". Try making all that a user's first lesson on how to use Opus!
"or did but was going to recreate it again in a moment. They would not want all their layouts to forget their folder tabs pointing at it": for an open lister, when a folder is removed, tabs should reflect that in real time. Layouts should interrogate the tablist when they are opened to verify that folder tabs do indeed pertain to existing folders. Layouts need not elimate the record of that folder tab, they just should not show it if the corresponding folder does not exist. Then, if the folder gets recreated, the tab should once again reappear. Windows file system notifications allow exactly these kinds of scenarios.