[otrs] OTRS 3.3.8 auto lock

Hi, I am using OTRS 3.3.8, and am experiencing an strange behaviour. I clicked Tickets -> Queue View -> Ticket number and then I navigated all of the sub menus, the ticket was locked by me after I clicked the Queue button (the button for moving tickets) but I didn’t click the “submit” button on the pop-up window. That is to say, I only browsed the pop-up window for the Queue and clicked the close button at the top right of the window, then the ticket was locked by me. Does it sound a right behaviour? Why is a ticked locked by just browsing some pop-up windows? Is there any config available to disable this? Thank you! Aaron