When we create applications for our Solution Center, they are designed to be able to be deployed right away. Part of our set up is to create a good looking form when using multiple tabs. Since these tabs are accessible on the device via buttons, etc, there's no need to have the actual tab take up space on the device screen.
When initially designing the form, we create a canvas size that is larger than the intented device's dimensions and place the tabs to the right. Once the application creation is finished, we reset the size to the correct dimensions for the mobile device. This hides the tabs.
In order to access these tabs to edit, go to Form Properties button in the form designer, set the size to custom, then add about 20 pixels to the width. This will reveal the tabs. Once you are finished editing, return the screen dimensions to that of your intended device.