bit of a weird one this, i dont know how i did it but if i have anything selected and the click on empty space it doesnt deselect like it it normaly does.
it either keeps the current selection or selects something else.
this also continues if i copy the project.
so im guessing something has been checked on or off
ive gone through all the settings from another project where this doesnt happen and made sure they are the same in the one where it does but nothing is different.
edit - just discovered this only happens in perspective view and camera view.