Column borders become mis-aligned to listbox header's border after resizing a brower's width

Steps to Reproduce:

1. run attached zul
2. resize a browser window width

Actual:

Column borders become mis-aligned to listbox header's border:

(I turn listcell borders to black in order to expose the mis-alignment issue.)

Expected:

When the zul is just loaded, column borders alignment is correct. They should be still well-aligned after a browser resizes.

Workaround

• reload the page after resizing the browser.
• set hflex="min" on the listbox, then it won't resize itself upon a browser's width.