I think this is a bug. It also happens on the handsontable website demo.
If you select a cell in the first row then right click the header, it does not select the whole column.
If you select any other row’s column and then right click the header, it selects the whole column.
See this screen cast (might have to enable flash): https://www.screencast.com/t/dgVegI77guu
Side note / Question:
Is there a method i can use to identify if a context menu was opened from a regular cell or a header cell? The reason i ask is because I’m trying to add a column rename input to the context menu, but only show it if the header was clicked. The bug reported is interfering with my workaround to achieve this (my workaround involves using the selected column index and looking for the class “ht__active_highlight”). Using selections does not help - the user could manually select all cells in a column, then right click for the context menu which is not the same as right clicking the header.
EDIT: To quote the documentation “Context menu with default options”: “Likewise, when the context menu for the column header is opened, the row options are disabled” - It looks like this uses selections too - and is also effected by the bug.