ListColumn.UserResizable
From Xojo Documentation
Property (As Boolean )
aListColumn.UserResizable = newBooleanValue
or
BooleanValue = aListColumn.UserResizable
Supported for all project types and targets.
or
BooleanValue = aListColumn.UserResizable
Supported for all project types and targets.
True if the column is resizable; the default is False.
Example
The following line in the Open event of a ListBox makes all the columns in the ListBox resizable: