Version 1.4.5 - sandbox or normal vault
When entering stacked tab mode the active tab is not kept and the leftmost tab becomes active.
seems similar to this closed report but may be unrelated:
Expected Behavior
Active tab remains in view and active when entering stacked tab mode
Actual Behavior
Stacked tab interface shows the left most tab when toggle stacked tabs is executed. (The previous tab is still active i.e you can type into it, though it won’t become visible)
Reproduction
Open sandbox vault → open multiple tabs → have a tab that isn’t the leftmost active → activate the “Toggle Stacked Tabs” command
Partial workaround
Pressing navigation keys up and down will bring you to the tab just before the previously active one, you will have to still scroll one more tab/click on the title bar.