Kerning problem (related to space)

I was trying to adjust the kerning between T and E. However, when I put a space bar between these two letters, the space between them decreases (it should be kerning + space). Also, when I click the kerning lock, it can’t be opened.
Can you tell me how to fix the problem? Thanks!

47

The kerning amount between the letter and space, and space and the following letter, is more than the the width of the space. In other words, you overkerned.

But looking at this, you should need not to need any kerning at all in this situation. I am pretty convinced this can be solved perfectly with spacing only, and no kerning at all. I would delete the kerning and try to improve the spacing first.

Please read the spacing tutorial: https://glyphsapp.com/tutorials/spacing

Thanks! How about the kerning lock? I can’t open it when I clicked the lock.
03

The looks are only interesting when you have kerning groups. Otherwise they have no meaning.