I could
not reproduce this with the two Edge versions I have access to:
Version 104.0.1293.47 (Official build) (64-bit)
Version 104.0.1293.63 (Official build) (64-bit)
This is on a Windows 10 machine, using Zen. I tried Bootstrap as well, same thing.
I've attached my testing app--maybe you can see what is different.
I did notice with all browsers that the framework has to "settle-in" before the width is available. For example, clicking on the menu option to open the form always worked when the code was called in the Load Event of the form. So next I I tried showing the form in the after login event. For that case the value was zero for all browsers. If I set a one second timer to fire to show the form (with the form.show command in a procedure that was linked to the timer) then it worked. In the end I just got rid of the load event of the form and moved the code to the form On Resize event so I could see it updated in real-time when resizing the browser window.
...jack