Before this patch the non-TypeScript version of the slide mode causes
problems with the TypeScript code. Therefore, in order to get things
working, this patch does minimalistic changes to the slide mode
controller to bring it into TypeScript convention. And unbreak slide
mode. Further changes are required, but this gets slide mode back to a
usable state.
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>