Steps to Reproduce

run the attachment hflex-min-columns-issue.zul

Current Result

the headers/cells are misaligned

Expected Result

correct alignment

Debug Info

the example contains a custom border style to highlight the issue (it can be removed still producing the same issue)

use iceblue, different themes might require different sizing to provoke the issue.
Very small changes to sizes, number of rows/columns, listbox width or cell content avoid the issue (commented out in the example)

The example contains a larger listbox showing the problem at a different size/column number