Can't open Dropdown via space bar in Firefox

Created by: smalltee129

• Operating system and version : Windows 7 Professional
• Browser and version : Firefox 47.0

In my project, i can't open dropdown menu by spacebar in firefox. steps:

1. focused on the dropdown components by tab
2. press "spacebar" one time
3. the menu is display, but then hide again.

expected result: the menu could be shown when press spacebar actual result: the menu not open correct.

After checked the demo in bootstrap(Dropup example, the attached file), i find the same issue also happen. Do you know this issue? or is there any method to resolve it? Thanks a lot.