[2phast]

The trim is inserted into the panel and the tabs are melted, thus holding the trim in place. You have two choices, remove the door panel and use a epoxy/hot glue to secure the tab or leave the door panel on and get some epoxy/hot glue to secure the trim. That might be messy, so maybe some strips of two sided tape onto the rear of the trim and press it back into place.

 

[2phast]

The hot glue I used didnt stick to anything, I'll try a bunch of double sided tape

It will work if you get it inside the hole that the peg goes in. Works well from the backside for sure, thats how I put my trim back on after I took it off. Sticks quite well to that fiberboard they use, can't say the same for their glue though, I had to glue the top section of the door panel (plastic rail assembly) back onto the fiberboard.

If neither works, go with a two part epoxy.

 

[2phast]

If you want to stick anything on a car with tape, the only thing I've found that works are the double sided 3M pads sold to fix mirrors, which you can get on small rolls. The problem with anything like this is it can come loose when the cabin gets hot.

Do you think this trim is aluminium or chrome on ABS plastic? I never had much success in the past with plastics but recently I've done some good small area repairs with a soldering iron set at the right temperature to replace tabs that have broken. I've even found thicker parts on a plastic trim and inserted a hot wire, sewing pin, or stainless weld wire, let it cool and used the new wire as an anchor point If you don't have a digital soldering iron you can switch it on and plastic weld quickly as it warms up. V.W usually mark the plastic type for recycling and you can buy short lengths of different type plastic filler sticks. Plastics welding only works using the correct filler rod and temperature. I've also tried using hot air, but it's less controllable than a hot iron and you can easily end up with a molten mess!

The part is made of PA6 GF (Polymide). The silver trim does feel like metal, not chrome though.