I'd like to add a few more "solutions" to the problem:
With the keyboard key "◄" you can collapse the current folder. For me it works good using the arrow keys "up/down" and collapsing with "left".
"Track active item" (@MarvinW) is not set by default, but during the training it is recommended and set. I think it helps beginners in the orientation because then the selection in the solution explorer and the open document are the same. If you deactivate this option you have to read the name of the open document carefully and ignore the selection in the solution explorer: If you deactivate "track active item" I recommend you one of the following options:
Open Tools > Options in the menu bar and choose a shortcut for "View.TrackActivityinSolutionExplorer", for example with shortcut CTRL+T. Everytime you press the shortcut, the currently open document will be selected in the solution explorer. So instead of the automatical selection you can choose when the solution explorer follows your open documents.
Activate the button "Preview Selected Item" in the solution explorer. It opens the documents (methods, FBs, ...) with just one click on the right side:
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