This dialog box opens during the Split Seam 
command and specifies the intersecting seams used to split the selected seam.
Execute
Select which splits to process.
Splitter Entity
Displays the seams intersecting the selected seam.
Is Bounded
Specifies if the intersecting seam is bounded to the selected seam.
Select All
Selects all the splitter entities.
Select None
Clears all the splitter entities.
Reject
Rejects the seam selection and clears the Split List.
You can directly click Select Seam(s) 
in the ribbon to select another seam to split without closing the Split List dialog box.
Accept
Refreshes the Split List to update the list of intersecting seams for the selected seam.
Finish
Splits the seam using the parameters you have defined. When the split process is complete, the Split List is cleared.