Can't use dropdown menu on pages.

For example go to https://copr.fedorainfracloud.org/coprs/g/kdesig/kde-nightly/builds/ and at the bottom of the table is a dropdwon to show x entries. 

In Firefox it drops down a menu just under it to show the options.

In Angelfish it flashes up some options in the center of the screen. If I hold my mouse down when clicking the field I can move the mouse to the new popup and use it. If I don't hold my mouse down it just vanishes.