Corrected entry: When Crewman Heron is in his escape pod informing Captain Janeway of his intentions a mouse pointer can be seen moving around on the LCARS display in front of him.
Corrected entry: In the episode "Good Shepherd", when the crewman is in the Delta Flyer's escape pod, look at the computer panel in front of his face. You can see a mouse cursor, which moves wildly about the screen after about a second, before the camera pans away. There are NO mouse cursors used on the computers in the 24th century, everything is touch sensitive.
Correction: Tom Paris, who designed the Flyer, states in some episodes that he's fascinated by old 20th century technology and incorporated many aspects of it into the workings of the Flyer. One of these features could have been a mouse cursor.
Correction: Submitted and corrected already. Tom is fascinated by 20th century technology, and incorporates many features of this era into the workings of the ship. One of these features could have been a mouse cursor.