NSTableView get rid blank space separating columns

I have an NSTableView with 4 columns. I also have a custom background color for each row. The only problem is I have these ugly white spaces where the gridlines would go in both the horizontal and vertical axis. I have both unchecked in IB, but they still show up. How can I get rid of the vertical ones and change the color and size of the horiz开发者_高级运维ontal ones?

Here's what I see: alt text http://img815.imageshack.us/img815/9030/homex.png

To get rid of vertical spaces but keep the horizontal ones:

[yourTableView setIntercellSpacing:NSMakeSize(0.0, 2.0)];

See Apple documentation for more details.

You'll need to override drawClipInRect to draw your own grid. The article I linked to modifies it so it only draws vertical gridlines. You'll have to modify it to only draw horizontal ones instead, but the basic strategy is the same: By overriding it, you can make it not draw vertical lines by simply not including the code for it.