I came across this scenario, thought of sharing so that will help others as well.
In Calculation view, when the name of Projection node is same as Table name added, activation fails with error.
Scenario: Add two projection nodes and add tables VBAK and VBUP to them. Name the projection nodes as same as table names i.e., VBAK and VBUP. Join the projection nodes and activate the view. Activation failed with error
“Floating Node VBAK found in this Calculation View”
“Floating Node VBUP found in this Calculation View”
After activation, when the view is closed and opened again, projection nodes are left as orphans in the model and the tables VBAK and VBUP are directly considered into the join.
Workaround: Change the projection node names other than VBAK and VBUP. Changing projection names to lowercase also works i.e., vbak and vbup. Or give meaningful names as TAB_VBAK and TAB_VBUP.
This has been proposed in SAP idea incubator, here. Hope this feature will be enabled in the next versions.