Unselect Item When Clicking Other Item

I've looked all over and tried to set up an action, but haven't been able to find it. When I click a different item or track or take, I'd like that new item that I clicked to be the only "selected" item. How can I do this? thx!

That's standard behaviour. Dont't press Ctrl while selecting items. (provided that mousemodifiers are default and your keyboard isn't defective)

1) Goto Reaper Preferences > Mouse Modifiers. 2) In Mouse Modifiers, choose context: media item , left click. 3) Now change Default Action to "Select Item".

i think default is right drag

UR Welcome !