GemRB supports various input gestures to facilitate playing with a touchscreen. Most gestures can be configured in the GemRB.cfg; although, at this time, only the number of fingers is configurable.
Keyboard show/hide: swipe up with 3 fingers to show; down to hide.
Console pop: swipe up with 3 fingers with the keyboard already showing.
Display Info (tab+alt) touch the viewport with 2 fingers.
Scroll the Viewport drag the viewport with 2 fingers.
Scroll text areas drag with any number of fingers except NumFingKBoard. TextAreas will scroll 1px for every px you move your finger.
Right Click click and hold for a right click.