I don't have a PC, as it says I need that newer version of Game Editor to read the file, but if I had a character that was sliding, I have to create a way for it to stop, and the best way to do that is with a path finish, provided there was a path to get the character started.
Since I can't see what the game is like and what the intent of the sliding is for, I can only give some very basic advice:
Let's say the actor collides with something that cause it to begin sliding on a path.
Actor/Add Collision Event/with Any Side of Actor 2/Script Editor
Variables/change path/Event Actor/path/slideright (create the path when prompted)/Axis/x axis
Then, to stop that path from repeating and stopping:
Actor/Add Path Finish/slideright/script editor/
ChangePath("Event Actor", "(none)", X_AXIS;
That's the general idea anyway. You can add conditions to that through variables, but that gets a lot more complex to explain.
I would help more, but am very booked up with other projects including my own game editor game project. Best of luck!