Get(TriggerCurrentTabPanel)
Purpose 
Returns the index and the object name of the current tab panel (the tab panel to be switched from) when the OnTabSwitch script trigger is activated.
Format 
Get(TriggerCurrentTabPanel)
Parameters 
None
Data type returned 
text
Originated in 
FileMaker Pro 12.0
Description 
Use with the Get(TriggerTargetTabPanel) function. Returns an index value, starting from 1, when running a script triggered by the OnTabSwitch script trigger, and the object name assigned to the tab panel. Returns 0 if the tab panel is invalid or if Get(TriggerCurrentTabPanel) is not used with the OnTabSwitch script trigger.
You can use the GetValue function to extract the value you want to use from the index value returned by Get(TriggerCurrentTabPanel).
Note  For information on how functions evaluate differently on the host versus the client, search the FileMaker Knowledge Base available at http://help.filemaker.com.
Examples 
When the tab panel to be switched from is tab number 1, named “Category,” Get(TriggerCurrentTabPanel) returns:
1
Category
Related topics 
Functions reference (category list)
Functions reference (alphabetical list)
About formulas
About functions
Defining calculation fields
Using operators in formulas