When you open a validation form the Tabs properties pane is displayed right of the validation form pane. If you select an element on the form or add an element to the validation form the corresponding properties pane is displayed instead of the tabs properties pane. Click on the tab to show the corresponding tab properties again.
You can set the following option:
Edit the text to change the default caption of the selected tab.
When you click the button to the right, the Translations window is displayed, where you can define different translations for the caption.