The latest couple versions of Transmission for OS X have had non-Mac-like behavior of the gear menu (lower left corner of the main window). The menu should pop up when the mouse is clicked, not when it is released. A rapid click-release cycle should leave the menu open until the user clicks again, either to select something from the menu, or by clicking elsewhere to dismiss the menu.
A click not followed by a release within a certain length of time (the behavior is standard, so I assume it's defined in the OS or interface guidelines) should instead only keep the menu open until the mouse button is released, and releasing the mouse button should then function as select if the cursor is still over the menu at that point.
Every other interface element of Transmission behaves correctly--the pulldowns in the Inspector, contextual menus in the main window, the main menus on the menubar--it's just this one bit. And earlier versions of Transmission behave properly, too. (I couldn't tell you exactly when it changed.)
Having to click-and-release in order to open a menu and then click-and-release again to select something from that menu (and again if there's a submenu, and so on) is one of the more annoying behaviors of MSWindows. All the extra clicking just to get things done not only is annoying, but painful in the aggregate (I never had wrist troubles until I started a job where I have to use Windows all day).
Using Transmission 2.77, build 14031; OS X 10.6.8, fully patched. Error persists on the latest nightly build (14074).