MOHAWK: Riven: Dome sliders differ from the original

[dafioram]

In the original engine for Riven the dome sliders that are dragged to enter dome code will stay vertically with the players cursor location as long as they are holding the button down.

In ScummVM the slider will only move when the players cursor is also in the area that the sliders can move in.

This can lead to a slider appearing to get stuck. E.x., if the player moves the cursor with the slider held from one side to the other with the cursor moving above of the slider area it will get stuck vertically when the player moved out of the slider area.

[dafioram]

Fixed in 51351111d4.