Thumb indication

A b3270 protocol message that indicates a change in the scrollbar thumb.

Example (XML)
&lt;thumb top="0.01031" shown="0.98969" saved="43" screen="43" back="0"/>

Example (JSON)
{ "thumb": { "top": 0.01031, "shown": 0.98969, "saved": 43, "screen": 43, "back": 0 } }