My sliding windows were missing the little plastic guides that go at the
bottom, and space the window in the lower track. Without these, your sliding
windows won't latch properly, and can be opened from the outside by anybody. 
Anyway, I ordered some but I can't get them to insert all the way into the
gap. Do you have to remove the glass to get them to tap all the way in?

I have them in as far as they will go, but not all the way.

At least my windows lock now...

anyone replaced these, and how did you get them to tap all the way flush?

chris