An error occurred while saving the commentJulian Turner commented
There has been an update to SharePoint at the end of March 2018 which has broken the user interface. Microsoft have added a great new feature that lets you multiple select files and folders by drawing a box around them. However, this has broken the UI in relation to widening and narrowing columns in a column view of the files and folders. A drag action defaults to the selection "box" and prevents columns from being widened.