nice detective work there
It seems that Firefox 35.0.1 when running on your device thinks that a touch screen is available.
Could it be that your PC has both a touch screen and a mouse? In which case, I guess the JMatch drag-and-drop works if you drag the items with your finger on the touch screen. Yes?
The edit you have made to "hp.js" will fix the isue on your device, but it will also disable the tap events on all other touchscreen devices, so for the long term we need to find a solution that works not only on devices that are have either a touchscren or a mouse, but also on devices that have both.
I may need your help with testing a solution, because I do not have physical access to such a device. But first, could you confirm whether or not your PC has a touchscreen, and, if you restore "hp-.js" to its original condition, whether or not you can drag-and-drop JMatch items with your finger on the touchscreen.