Web v desktop pixel sizes

I am converting some reports from a desktop app to a web app. The reports are displayed in listboxes that are 661 pixels wide. I am not understanding the differences I am seeing in the size of the boxes and the information in them. The obvious workaround is to make the weblistbox wider. But why are they different sizes on the screen when they are supposed to be the same width? The screen shot shows the desktop app overlayed on the browser using the same data.

The browser controls scaling size depending on user preference. See if you have that set to 100%

Browser scaling does make the whole page bigger or smaller, but it doesn’t do anything about cutting off most of the last column on the right.

I widened the listbox to 695 pixel from 661 and the the right hand column was still cut off. Column width was “15,75,120,,,,,". I changed it to “15,75,120,97,97,97,97,97” (total=695) and there was no change. Changing it to “15,65,120,90,70,90,90,90” (total=630) makes everything display properly. Changing the last “90” to "” causes the value in the right hand column to no show. This may be a bug. I am using 2014r3.2. It does the same thing in 2016r3.