Handle came off sliding window in my destination trlr

I like goop too.
this is a sliding window,.. so if you had to you could use a suction cup device to slide it. the issue is really that the handle is often also the locking device.

So long as the slider is on the INSIDSE a small length of dowel rod or hakf or quarter round (i'd use quarter) layed in the track works well

or drill STRAIGHT down and drop in a bolt or pin Drop in means lift out,.