I have removed all width sets from the entire component except for Style="width: 1800px". The screen width is equally distributed among the columns now, which is good. However I still need Style=width because when I resize the browser, the columns are re-rendered based on the new width. Therefore they are getting even smaller. I want a horizontal scroll to appear, which it does but it is of the browser, not of the DataGrid.
I don't think DataGrid's scrollbar will appear without widths. Am I wrong?
I have added more columns. This is how it's look like now:
Only the first column has a fixed width.