If you test DDR skins with IE 9, 10, 11, Chrome and Firefox on any Windows OS (Windows 7 or Windows 8), and a touch screen, the drop-down menu does not work correctly.
Pressing momentarily causes the drop-down to expand, but letting go of the touch, the menu collapses immediately. If you press long enough, the menu does appear, but the Windows Copy/Paste function overlays it.
This is because in the Windows Touch environment, a sustained touch is the same as right-click on a mouse. You cannot select any drop-down item because of this.
This is true on custom skins and on the default Gravity skin as well.
As far as phone/tablets, the issue is probably being somewhat addressed by the new responsive skins, but I have found only one developer who has 'fixed' this problem. But, now that Windows 8 phones are approaching 10 percent in the U.S. market and over 15 percent in several European markets, this should be resolved immediately.
This has been reported in Gemini, issue DNN-23998