Help Needed: Unable to Select Individual Rows in Lead List

hey guys similar to the column visibility issue above... The problem I'm having is being able to select individual person(s) from a box that you would usually see once you hover over this area (see marked), it's now gone and if I want to delete different rows then I have to click the top box to select all and then untick from there which is highly inefficient from a lead list of 2000+. Help!