Hide/Unhide is not working properly in case of grid having merge cells.

I have multiple headers(attach headers) in my grid. when I called hide on merge header column , It works fine but when I did unhide it messed up.

The next column to merge cell displays with no attach header.

The setColumnHidden will not work correctly if you call it against column which included in colspan on one of header rows - this is known limitation.
( you can’t hide or show part of column which included in colspan, all columns which included in colspan must be shown|hidden in same time )