Patel I found you can use spaces in the text of the header. It is not the best method since text spaces vary with font size and in your case shown here it would be many spaces causing much variance.
For me it was only a few spaces and it happened to work out for both extremes of screen size. I would be happy to show the blocks but they just wont help in this example. Perhaps you could use ascii 160 or other padding?
Ascii 32 is a "space" in common text and its width, but not height, vary with changes in font size. Ascii 160 appears as a space on screen in most software but its width remains consistent with font width.
In HTML it is called a "sticky" header and you must use extensive CSS to make it stick. The CSS stops sticking as soon as you "pinch" expand or shrink screen size so the CSS is useless on anything but PC. For me it is not logical to call a header that does not "stick" a header! If it does not head the page then its not a header right?
For you Patel I can only suggest padding such as extra text characters.For Instance: instead of "USER" maybe "Name:Last, Middle, First" might work? I got lucky with mine since each column (except the left most one) were narrow and the differences in display were minute.
Where is Ken? Maybe it would be nice to have a version 4? I read endless internet queries from people wanting a TableView like this with a true header. The searching for a HeaderBar is very much needed.
Hope this helps and let me know if I can help further