I recently shattered a tempered glass sliding shower door whilst removing it for cleaning. (Lesson learned: always clean shower doors in situ - they needn't be removed).
The shattered door was eventually replaced - however the towel bar assembly was not included. (It is a ten-part item: two aluminum clips to connect two aluminum bars to the door, two rubber sleeves -- 'glazing channels' -- to ensure a snug fit between the glass door and the clips, and four screws to fasten the bars to the clips).
Fortunately, I still had the old assembly, but - Unfortunately - the clips were full of broken glass. In the process of digging out these shards with a screwdriver (as directed by the supplier, ACME Glass, of Surrey, BC), the glazing channels were shredded, so that they looked like mere tatters of black electrician's tape. Without them, the clips don't clip to the door, they just slide around.
Fortunately, ACME was kind enough to mail new glazing channels (although, Unfortunately, their policy doesn`t allow them to install a towel bar on a replacement door - without charging a fee). Unfortunately, the glazing channels + clips fit so tightly that there is a high risk of shattering the glass again while installing them.
This is my current predicament.