From a fresh load of my page the tabs overlap the pane. Once I click refresh, everything looks normal.

I am using left-h as the tabPosition and the contentpane is wider than it should be overlapping with the tabs.

The dijitTabPaneWrapper div from a fresh load has a width of 504 and becomes 486 after I reload the browser. Where is this 20px coming from that doesn't happen after a page reload? :)