Getting duplicate header button cell in NSTableView when using NSPopUpButtonCell

Question

I have a dynamic NSTableView which can add a number of columns depending on the data provided. For each column I have set the header cell to be a NSPopUpButtonCell. (Side-note: I've had to use a custom subclass class for NSTableHeaderView otherwise the menu doesn't pop-up). All works well, apart from a duplicate or extra header button cell on the top right. It mirrors perfectly the previous column selection as shown in screenshots. My question is how do I stop the NSTableView from recycling the previous popup header cell? (By the way I have tried the setCornerView method but that only effects the header area above the vertical scrollbar.)

Answer 1

I have this issue and i don't use NSPopUpButtonCell at all. I just want to tell about other method how to hide this odd header. This methods will not remove an odd table column, i.e. if you have 2 'legal' columns and hide this extra 3rd column header, you will still be able to move separator between 2nd and 3rd column. But in this case you won't see redundant header even if you want to resize any column. I still need solution how to completely remove the redundant column, and why this is happening. (and why Apple won't fix this bug?)

So... you can just calculate index of column which this header belongs to and according to this draw your header or don't. First, subclass NSTableHeaderCell and set it as a cell class for columns. Let assume your subclass named TableHeaderCell:

for column in self.tableView.tableColumns {
    let col:NSTableColumn = column as! NSTableColumn
    //you can operate with header cells even for view-based tableView's 
    //although the documentation says otherwise.
    col.headerCell = TableHeaderCell(textCell: col.title) 
    //or what initialiser you will have
}

Then in TableHeaderCell's drawWithFrame method you should have:

override func drawWithFrame(cellFrame: NSRect, inView controlView: NSView) {
    let headerView = controlView as! HashTableHeaderView
    let columnIndex = headerView.columnAtPoint(cellFrame.origin)
    if columnIndex == -1 {
        return
    }

    //parent's drawWithFrame or your own draw logic:
    super.drawWithFrame(cellFrame, inView: controlView)
}

After this you won't have redundant header drawn because it not belongs to any column and columnAtPoint method will return -1.