Number-of-characters-per-line not respected in one editor tab after font size is changed in another editor tab

Environment

• TeXstudio: 2.12.8
• Qt: 5.8.0
• OS: Windows10
• TeX distribution: miktex

Expected behavior

The font size and the right borderline in the editor should match so that the number-of-characters-per-line is as given in the settings.

Actual behavior

In the scenario described below, the right borderline in one editor tab is not updated accordingly when the font size is changed in another editor tab. To make them match again, a manual change to the font size is needed.

How to reproduce

1. open two documents; set the maximum number of characters in a line; enable zooming with mouse wheel;
2. switch to document 1;
   
3. switch to document 2;
4. Increase/Decrease font size using mouse wheel when document 2 is open;
5. switch back to document 1.
   The font size of document 1 has changed, but the right borderline is not.
   When font size is increased:
   
   When font size is decreased:
   

(The line on the right side of each image corresponds to where the maximum number of characters is reached)

Reproduce the two-document scenario in the editor with mouse-wheel zooming and a configured maximum line length. Trace how font-size changes propagate between editor tabs and how the right borderline is recalculated; done means the border in document 1 matches the configured character limit after changing the font size in document 2.