~~Title: OnSourceDestChange ~~
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The **OnSourceDestChange** event can be implemented by a [[:scripting:script_add-ins|script add-in]] to receive notification whenever a tab's source/destination state changes.


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$$ (#)**Method Name:**
$$ OnSourceDestChange
$$ (#)**Argument Type:**
$$ **[[..:scripting_objects:sourcedestdata|SourceDestData]]** 
$$ (#)**Return Type:**
$$ //none//
$$ (#)**Description:**
$$ The **SourceDestData.tab** property identifies the tab, and the **source** and **dest** properties identify the new state (if both are **False** it means the tab is "off" - this can only happen in a single file-display Lister).
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