It isn't padding or styling that is causing this. From what I can see, the tabs that do have the gap also have two actual space characters after the tab names. Have you added spaces manually to the tab names?

Or.. have a look in your skin file and see if there is a solpart attribute that is adding "  " somehwere. I have seen that in some menus... possily as a divider.

Rob

hmm.. hard to say... although the more I thought about it the other day, the more I was convinced that it was an intentional design choice.

It would have been in the ascx file if it were there, possibly called rootmenuitemrighthtml.

DNNCreative has a sub-site with all solpart menu details. I can't find it because his site also seems to be dead. Try dnncreative.com and if it is back online, look for a link through to his skinning site. Otherwise, have a dig through other skins with vertical menus and see what you can come up with. I've had a look at a couple of mine and there's nothing obvious to me, but you might spot something given that you also can see your ascx.

Let me know if you figure it out.

Rob

To Rob:

Thanks Rob, I do have "rootmenuitemlefthtml" and "rootmenuitemrighthtml" in my homepage and 2ndlevel skin files, but they all equal to nothing. And if it's because this attribute, why would mainmenus become offset only when they have submenus?

I have found the answer in the spmenu.js file that Peter metioned. I searched ' ' in that file and there is a line called 'spm_getArrow(this.rootArrowImage, this) + "", ' ')'. I deleted the ' ' and it works on the site. But I still need to thank you for all the help. :) 

To Peter:

I had no knowledge about JavaScript at all, but fortunately there are only 4 ' ' in the js file. Like I metioned above, the problme is solved and a great thank to you!

Ummm.. I really want to move on from the DNNSolpartMenu to the DNNMenuNavigation, but I just don't know where to start. Do you know any tutorial that teaches how to configure DNNMenuNavigation? It would be great if you can suggest some useful website. Thanks again!