Callback that reports how many consecutive headers (rows or columns) are hidden starting at index. Returns 0 when index itself is visible. Used to skip hidden headers while traversing.
index
0
The header index to test.
Optional
Scan toward lower indices (used when moving Up/Left).
Callback that reports how many consecutive headers (rows or columns) are hidden starting at
index. Returns0whenindexitself is visible. Used to skip hidden headers while traversing.