TestComplete can minimize to the taskbar during test runs so that it does not overlap your tested application. This is controlled by the Minimize TestComplete option in your TestComplete project properties. To enable this option:
Select Tools > Current Project Properties from the TestComplete menu.
Choose the Playback category in the list on the left.
Select the Minimize TestComplete check box.
Select File > Save from the TestComplete menu to save the changes.
Running Tests - Tips
Project Properties - Playback Options