Sent to a group when you go to the card that contains it and to a group when going from a card which it is not placed on to one where it is.
# Metadata
Platforms: desktop, server, mobile OS: mac, windows, linux, ios, android Introduced: 3.5 Security:
# Syntax
preOpenControl
# Examples
on preOpenControl resizeMyObjects put empty into field "Customer Address" of me end preOpenControl
# Description
Handle the preOpenControl message to update a group's appearance before it appears on screen.
For groups with their backgroundBehavior property set to true, the preOpenControl message is sent immediately after the preOpenBackground message is sent to the card being opened. For non-background groups, it is sent after the preOpenCard message.
For nested groups, the preOpenControl message is sent to the parent group first, if it is passed or not handled by the parent group, then it passes through each child group in reverse layer order (i.e from highest to lowest).
The actual navigation is not triggered by the preOpenControl message, so blocking the message and not allowing it to pass does not prevent the card with the group from opening.
# Tags
# See
- **keyword:** card - **property:** backgroundBehavior - **message:** preOpenBackground, openControl, preOpenCard - **command:** dispatch - **object:** card, group - **glossary:** message, property