After completing both try outs on p222 and p226 I seem to be having a few problems.
If I leave Monochrome as the page attribute in the web config file then Monochrome will work OK. When I change the page to DarkGrey in the Browser then the page seems to morph into something in betweeen Monochrome and DarkGrey. Again, if I reverse this and insert DarkGrey into the web config file attribute, DarkGrey will work fine. However, when I change it to Monochrome a similar thing happens (morphing both themes).
If I leave the attibute empty in the web config file then they both work OK until I empty the cookies in the Browser, then I get a page with no formatting when opened. When I select any theme it starts to work OK again. Obviously I will need to leave one of the themes in the web config file as a default. The page Default.aspx does inerit from BasePage. Any ideas as to what could be causing this strange behaviour? Tearing my hair out here. All advice gratefully recieved