I'm just tested the other issue when I found this.
The window size is depend on the content, like Game names or achievement description.
If the game has an achievement with a long description the window width will be long enough to be out of screen.
For example PayDay 2's Wind of Change achievement has a very long description which made the window width to 2701px, which is only usable on ultra wide monitors (or dual monitors).
I'm just tested the other issue when I found this.
The window size is depend on the content, like Game names or achievement description.
If the game has an achievement with a long description the window width will be long enough to be out of screen. For example PayDay 2's Wind of Change achievement has a very long description which made the window width to 2701px, which is only usable on ultra wide monitors (or dual monitors).