Gets the width of each tab, in pixels.
The default value is undefined. When this property is undefined, the width of each tab is determined by the width of its label text, using the font styles applied to this TabNavigator container. If the total width of the tabs would be greater than the width of the TabNavigator container, the calculated tab width is decreased, but only to a minimum of 30 pixels. If you set this property, the specified value overrides this calculation.
The label text on a tab is truncated if it does not fit in the tab. If a tab label is truncated, a tooltip with the full label text is displayed when a user rolls the mouse over the tab.