When I got by bike I had an oil leak on the right hand side, down by the oil window.  I removed casing cleaned it up and put in a new gasket.  This spring before I put in the new improved cam chain tensioner from Verslagen, it was leaking again.  I installed the tensioner and cleaned up the surface of the casing and installed a new gasket.  I am quite sure in all instances that I tightened everything down to the right torque on a diagonal.  I have been keeping watch and the oil has been showing about midway in the window and no oil showing leaking on the outside casing.  Yesterday I went into town and I noticed oil showing on the casing and nothing showing in the window.  
When I replace the gasket again I am thinking of putting some liquid gasket sealer on the casing.
Has anybody else ran into this problem  and is my idea of using sealer plus gasket the way to go?
DocNeedles