Thanks for giving us your feedback. Straight to the questions at hand. The MasterType issue that you report was also reported by others. We are aware of it and a fix is already on its way. At the end of this week a new build will be available where this issue will be fixed.
As for your second question - in the error list we show only the file name currently. If you hover over some file name as a tooltip you will see the full file path to that file. Double-clicking on some error/warning will navigate to that error/warning. However, your suggestion sounds reasonable and we will include it to our product backlog for future implementation.
Your third request is also something that we have already spotted. Those warnings shouldn't be reported by JustCode. We have it scheduled for fixing in one of the following releases.
In case there are errors/warnings that you consider incorrectly reported you can ignore those either by using the context menu in the Error List or using the Quick fix context menu (Alt + Enter) when the cursor is over the particular error/warning.
In case you have some more questions or problems, don't hesitate to wright back.
the Telerik team