Crop To Content removing non-empty borders

[Krikor]

(04-28-2021, 10:42 PM)Ofnuts Wrote: What you want to do looks more like Layer ➤ Transparency ➤ Alpha to selection  followed by Layer ➤ Crop to content.

Ohhh ... I have always interpreted and used this function in the wrong way! 
The interesting thing is that it always seemed to work as desired. 

Were it not for the fact that I had done an experiment with the image displayed in post #1 and noticed the difference in the expected result, my understanding of this procedure would remain wrong for a few more centuries. 

Fortunately, the reading suggested by you solved the issue.

However, the comment made by Ofnuts left me intrigued. This led me to an investigation into the option he suggested.

I ended up discovering a subtle difference responsible for my misinterpretation of this Crop To Content command.

In the image below there are two particular situations:
1-➤ The layer is not the same size as the image (canvas).
2-➤ The layer and the image (canvas) are the same size.

When the first situation occurs (possibly the reason for my confusion) it is possible to simply apply Crop to content directly.
This will do exactly the same as the steps indicated by Ofnuts, only more direct (less menus = Layer ➤ Transparency ➤ Alpha to selection  followed by Layer ➤ Crop to content)

However, if the situation is that of the second case, and the image has a homogeneous color border, it will be removed - Case of the image posted in post #1.

Applying Layer ➤ Transparency ➤ Alpha to selection followed by Layer ➤ Crop to content, in the two situations in the image below:
   

cli345 and Ofnuts, thank you very much for clarifying this doubt.