Context Menu show problem

Hi! I have a problem with my context menu.... I have a tray icon and a context menu for the icon, this context menu appears if i right click the icon. because i want to open the context menu with the left mouse click too, i added a trayicon mouse event handler (mouseup) in the trayicon_mouseup function i tried to show the context menu with contextmenu.show(this,cursor.position) but this works only if the application isn't hidden!!! what can i do to show the context menu while the application is hidden? and how can i make the context menu after the left mouse click appear at the same position than the right click context menu? ^^ thx for help