When a tab panel has more tabs than it can fit in its width, then tab scroll buttons will appear:
(These buttons became available with the Profound UI Version 5, Fix Pack 5.0.)
Holding down a tab scroll button will cause the tabs to scroll. The longer a button is held down, the faster the tabs will scroll.
Speed and Acceleration
The pui["tabpanel scroll speed"] option sets the initial "speed" that the tabs will scroll. The default is 5–meaning that the tabs scroll 5 pixels in a certain, short period of time. Increasing the scroll "speed" gives the effect that the tabs begin to scroll faster.
The pui["tabpanel scroll acceleration"] sets how quickly the tab speed will increase in a certain period of time. Increasing the "acceleration" makes the tabs reach a higher speed faster. The default is 1.
Scroll Button Style
By default the scroll buttons use the same style as the selected tab. To render the scroll buttons in the style of an un-selected tab, set the pui["tabpanel scroll unsel style"] option.
Where do you save this configuration option? Here.