Steps to reproduce on FF/IE (Chrome works fine)
Step 1: Tab in first listbox
Step 2: Press down arrow key to change selection to "test 2"
Step 3: Tab out of first listbox
Step 4: Press down arrow key to select second listbox value
After step 3 above listbox2 should be updated with new values and focus should be on it so the step 4 selection is done
After step 3 above listbox2 is updated with new values but focus is lost. Pressing down arrow key does not chage value in listbox2 as focus is removed
This behavior happens on 5.0.12FL and 6.5FL but works as expected on 6.0.x (for chrome works well on any ZK version)