In Excel, the cursor changes to look like <-I-> when it is in the correct position to start resizing (column or row), and stays the same when the user is doing the resize - good visual feedback.

In RadSpreadsheet, we get a similar <-I-> cursor when in position to re-size, but this goes away (back to the normal pointer) whilst the user is re-sizing. The re-size operation works just fine, but I don't get the feedback whilst doing it.

Please refer to the two gif files illustrating the behavior in MS Excel and in RadSpreadsheet.