Tabbing in select not selecting option.

 Describe the error in 1 sentence
When tabbing into a select and arrowing down to option then pressing tab. The option isn't selected. 

Steps to reproduce
Tab into a select. Arrow down to an option and then press tab. The option isn't selected.

What exactly is supposed to happen
Tab into the select. Arrow down to the option and tab out of select and the option is selected. 
