Texture Application and Camera Manipulation
Moving the 3D camera in Texture Application mode
Instead of switching to the Camera Tool to move the camera, use one of the several Hammer Keyboard Shortcuts available to move the camera. When using the keyboard shortcuts to move the 3D camera position, you do not have to close the Texture Application window.
Getting "locked" in the 3D viewport when using shortcuts
When using camera keyboard shortcuts while the Face Edit window is open, it's possible to get into a state where the 3D view is stuck in navigation mode.
This occurs when the Texture Application window is over the center of the 3D view, and the Spacebar or other keyboard shortcut is used to navigate in the 3D view. If this happens, simply left-click to restore the Texture Application as the active viewport. A workaround is to move the Texture Application view to the side before attempting to change the camera position in the 3D viewport.