Basically, on the right side of the steering handle on my bicycle, the "soft" (not really) rubber thing that you grip with your hand keeps sliding slowly from its proper position down to this position, where it stops. As you can see, there's a big gap between the gear selector and the grip, which you can really feel while trying to bicycle around. It's extremely annoying. It ruins every trip because I keep thinking about it.
The red dashes on the photo indicate where the metallic part ends inside. It never seems to go further than that. If I use extreme efforts to slowly rotate it back into its correct location (that is, no visible metallic part), which only works sometimes depending on the weather, it soon goes back down again. So it's pointless.
Is this a common problem with an easy solution? The left side (which has no gear selector, obviously, if that matters) always stays in its right place.
Even if I use some kind of oil or grease or something to make it easily slide up again, it just won't stick in its proper place for long. I don't even understand how this is physically possible.