diff --git a/client/src/components/Workflow/Editor/modules/terminals.js b/client/src/components/Workflow/Editor/modules/terminals.js
index 918c4ed963c..3820250ef76 100644
--- a/client/src/components/Workflow/Editor/modules/terminals.js
+++ b/client/src/components/Workflow/Editor/modules/terminals.js
@@ -333,6 +333,11 @@ class BaseInputTerminal extends Terminal {
     }
     _producesAcceptableDatatype(other) {
         // other is a non-collection output...
+
+        if (other instanceof OutputParameterTerminal) {
+            return new ConnectionAcceptable(false, "Cannot connect workflow parameter to data input.");
+        }
+
         for (const t in this.datatypes) {
             const thisDatatype = this.datatypes[t];
             if (thisDatatype == "input") {
diff --git a/lib/galaxy_test/selenium/test_workflow_editor.py b/lib/galaxy_test/selenium/test_workflow_editor.py
index 831a499847f..1ceda16a6e4 100644
--- a/lib/galaxy_test/selenium/test_workflow_editor.py
+++ b/lib/galaxy_test/selenium/test_workflow_editor.py
@@ -241,6 +241,9 @@ steps:
     label: tool_exec
     in:
       inttest: input_int
+  cat1:
+    # regression test, ensures connecting works in the presence of data input terminals
+    tool_id: cat1
 """
         )
         self.screenshot("workflow_editor_parameter_connection_simple")