System Variables:

@SPM=1, PriorityMatrix

@SPM=2, PriorityWorksheet

@SPM=3, PriorityHolderImage

@SPM=4, PriorityMatImage

@SPM=5, PriorityHolderGraph

@SPM=6, PriorityGraphNotOpen

@SPM=7, PriorityGraph

where "Holder" refers to a Graph or Matrix added to a Workbook as a Sheet, and if a Matrix, View must be Image Mode (View: Image Mode).

The variable determines if a given window type will be elevated to "Must Use if Active".

The value of @SPM is stored in the Windows registry and will persist across Origin sessions until it is again changed.