im using blender 2.8 since my udemy course is using it.The problem that im having is i can't left click and drag to select multiple objects and i am using the selection box tool too but if i use the "Select Lasso" and "select Circle" they work just fine at selecting multiple objects. If i press the "B" key to select objects, that doesnt work either and i have tried defferent versions of 2.8 and i still have the same problem.
Just a thought. And this is probably way late. Hope you figured it out if I am wrong. But make sure that you have the "modeling" option selected at the top menu