Steps to Reproduce:
1.Click on a file
2.Still doesn't open a new tab
Does this issue occur when all extensions are disabled?: Yes
Guys I did some research and to open a new tab I had to disable preview mode. I did and it still doesn't work.

What setting did you change to disable preview mode?
Do you know that if you open a file from the Explorer by double click instead of single click it won't be in preview mode?
Also, double click the preview mode tab (italic label) to make it persist.
@gjsjohnmurray
"workbench.editor.enablePreview": false
like you're supposed to
This is a laptop and double clicking the touchpad doesn't work
also what's the preview mode tab?
You have set workbench.editor.showTabs to false. Therefore no tabs.
@gjsjohnmurray Thank you so much! It was driving me insane! I didn't know I implemented these changes!
Glad to have helped. Please close your issue.
Most helpful comment
You have set
workbench.editor.showTabsto false. Therefore no tabs.