Weblistbox ColumnCount increase makes the horizontal ScrollBar disappear

I have a WebListBox with 4 columns, totalling more than the width of the control, so the horizontal scrollbar shows.

If I go

ListBox1.ColumnCount = ListBox1.ColumnCount +1

a new column width “*” is added, but the horizontal scrollbar disappears, although the existing columns largely exceed the width of the control.

Only when I set the last column as a numerical value, would that be “0”, does the horizontal scrollbar comes back.

I am inclined to call that a bug.


Does it do that on all browsers or just one?

On Mac : Chrome, Safari, Firefox. On PC : IE 11, Edge, Opera, Chrome.

In all of them, the horizontal scrollbar goes away. Strangely enough, I looked at the DOM, hscroll is there, with visibility visible. But it does not show anymore.