I keep trying to add/remove buttons to my Solidworks (2020, SP5) Standard Toolbar. Every time I make the desired customization changes & then exit Solidworks. Upon re-opening Soldiworks, the changes that I made did not save.

This is extremely frustrating -- is there a reason for this? See screenshot for buttons I'm trying to change (trying to remove the buttons to the left of the Flow icon -- but it always reverts back):