How to open a folder inside a folder, without closing the first?

Question

I can't find a way to open a sub-folder, inside a mainfolder, without closing the main folder.
What's even worse, if you hold "option" or "command,"  (old OS9 muscle memory kicking in) it opens the new folder but wipes-out the ability to use the back button!  So then if you needed that main folder open, and it's deep inside some chain, you have to go searching for it again.
So, is there any fix for this?
<Edited by Host>

Answer 1

Problems such as yours are sometimes caused by files that should belong to you but are locked or have wrong permissions. This procedure will check for such files. It makes no changes and therefore will not, in itself, solve your problem.
First, empty the Trash, if possible.
Triple-click anywhere in the line below on this page to select it, then copy the selected text to the Clipboard by pressing the key combination command-C:
find ~ $TMPDIR.. \( -flags +sappnd,schg,uappnd,uchg -o ! -user $UID -o ! -perm -600 -o -acl \) 2> /dev/null | wc -l
Launch the Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
Paste into the Terminal window (command-V). The command may take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear.
The output of this command, on a line directly below what you entered, will be a number such as "41." Please post it in a reply.