Why is CTRL+Z (Undo) and CTRL+Y (Redo) being blocked and/or overridden in Zoho Social textboxes?

Why is CTRL+Z (Undo) and CTRL+Y (Redo) being blocked and/or overridden in Zoho Social textboxes?

When we type a long content it is necessary for the basic text editor shortcuts like CTRL+Z (for Undo) and CTRL+Y (redo).

Not sure why Zoho Social has blocked and/or oroverriden these keyboard accelerators!