1. A mobile communication device, comprising: a housing having a form factor suitable for handheld use; a display screen carried by the housing; a touch-sensitive input component configured to receive user input to the mobile communication device based on gestures on the touch-sensitive input component; a storage component configured to store a mobile application; a processor configured to execute the mobile application; a first window control component associated with a first application and configured to control a first interface displayed on a first portion of the display screen and to respond to inputs directed to the first portion of the display screen, wherein the first interface displayed on the first portion of the display screen is configured to simultaneously display the first application and receive user input; a second window control component associated with a second application and configured to control a second interface displayed on a second portion of the display screen and to respond to inputs directed to the second portion of the display screen, wherein the second interface displayed on the second portion of the display screen is configured to simultaneously display the second application and receive user input; and a coordinator component configured to generate a command from the first application to the second application in response to a user gesture to the touch-sensitive input component indicating an interaction between the first portion of the display screen and the second portion of the display screen, to provide the command from the first application to the second application, and to selectively enable or disable the first window control component and the second window control component to switch the mobile communication device between a single window mode and a dual window mode; wherein when the mobile communication device is in the dual window mode, the mobile communication device simultaneously displays the first interface and the second interface.