I think you need at leas two clicks, one to select the edge, the other to activate the command....
When you look in the API help, you can find this code (VBA) on how to create a flange.
Public Sub FlangeWidthsCreation()
' Create a new sheet metal document.
Dim sheetMetalDoc As PartDocument
Set sheetMetalDoc = ThisApplication.Documents.Add(kPartDocumentObject, _
ThisApplication.FileManager.GetTemplateFile(kPartDocumentObject, , , "{9C464203-9BAE-11D3-8BAD-0060B0CE6BB4}"))
' Get the sheet metal component definition.
Dim smCompDef As SheetMetalComponentDefinition
Set smCompDef = sheetMetalDoc.ComponentDefinition
' Create a sketch on the x-y plane.
Dim sketch As PlanarSketch
Set sketch = smCompDef.Sketches.Add(smCompDef.WorkPlanes.Item(3))
Dim tg As TransientGeometry
Set tg = ThisApplication.TransientGeometry
' Draw a rectangle.
Call sketch.SketchLines.AddAsTwoPointRectangle(tg.CreatePoint2d(0, 0), tg.CreatePoint2d(25, 15))
' Create a profile.
Dim profile As profile
Set profile = sketch.Profiles.AddForSolid
Dim smFeatures As SheetMetalFeatures
Set smFeatures = smCompDef.Features
' Build up a face feature definition.
Dim faceDef As FaceFeatureDefinition
Set faceDef = smFeatures.FaceFeatures.CreateFaceFeatureDefinition(profile)
' Create a face feature.
Dim faceFeature As faceFeature
Set faceFeature = smFeatures.FaceFeatures.Add(faceDef)
' Get the "top" face.
Dim topFace As face
Set topFace = smCompDef.SurfaceBodies.Item(1).LocateUsingPoint(kFaceObject, tg.CreatePoint(5, 5, smCompDef.Thickness.Value))
' Create a collection containing the four edges.
Dim edgeSet As EdgeCollection
Set edgeSet = ThisApplication.TransientObjects.CreateEdgeCollection
Dim i As Integer
For i = 1 To 4
Call edgeSet.Add(topFace.Edges.Item(i))
Next
' Create the flange definition.
Dim flangeDef As FlangeDefinition
Set flangeDef = smFeatures.FlangeFeatures.CreateFlangeDefinition(edgeSet, "90", 6)
' Edit the definition to define a different width extent for each edge.
For i = 1 To 4
Dim faceEdge As Edge
Set faceEdge = edgeSet.Item(i)
Select Case i
Case 1
' Do nothing and let it default to the edge extent.
Case 2
' Edit the width extent to be centered.
Call flangeDef.SetCenteredWidthExtent(faceEdge, 10)
Case 3
' Edit the width extent to be offset as measured from the vertices of the edge.
Call flangeDef.SetOffsetWidthExtent(faceEdge, faceEdge.StartVertex, 2, faceEdge.StopVertex, 5)
Case 4
' Edit the width extent to be an offset width extent.
Call flangeDef.SetWidthOffsetWidthExtent(faceEdge, 6, 2, faceEdge.StartVertex, True)
End Select
Next
' Create the flange.
Call smFeatures.FlangeFeatures.Add(flangeDef)
End Sub
If this answers your question then please select "Accept as Solution"
Kudo's are also appreciated

Succes on your project, and have a nice day
Herm Jan