Calendar widget, month - In popup, the columns are not spread evenly - last column is huge

Does anybody experience this as well? If you click the button to go a month forward or backward, the columns are spread correctly. The wrong column spreading only happens when you open the popup with the calendar. As this is the normal usage, it is awkward. I'm using Mx4.3.1.
1 answers

The bug is in the non-default popup size.

If you leave the popup size default, the columns are spread evenly. If you change them to 1500 x 1000 for instance, the last column gets all the extra space.