can't unhide 0px-width columns via header context menu

Steps to Reproduce

1. run the zul attached in KEIKAI-354
2. click the button to hide 5 columns
3. select column A:G
4. right-click the column header, select "Unhide" to unhide those 5 columns

Current Result

those 5 columns don't appear

Expected Result

those 5 columns are visible

Debug Information

• ZSS 3.9.6 also has this bug
• users can drag the column border to unhide the hidden column

Workaround

• drag the column border to unhide a hidden column one by one