I was in the 'Manage Projects' page for a specific project checking the categories.  I wanted to then see the issues for a project.  I decided to switch to a new project first (and then eventually click view issues).  If I am in any of my specific project pages under the manage option  I get an error whenever I click on a project in the bar or select any project from the dropdown menu. 
A required parameter to this page (project_id) was not found.
Please use the "Back" button in your web browser to return to the previous page. There you can correct whatever problems were identified in this error or select another action. You can also click an option from the menu bar to go directly to a new section.
Of course this is no big deal - because you can just click the view issues or whatever page you want and then change to the selected project and it works.  So it's not really a problem - but you should be able to click or select any other page from another without error.
I am running Mantis 1.1.1.  

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