refine checks to determine whether or not the port is exposed on frame

nodeEditor/src/diagram/nodePort.ts

@@ -51,7 +51,7 @@ export class NodePort {
     }
 
     public get exposedOnFrame() {
-        return this._exposedOnFrame;
+        return this._exposedOnFrame || this.connectionPoint.isConnected;
     }
 
     public set exposedOnFrame(value: boolean) {

src/Materials/Node/nodeMaterialBlockConnectionPoint.ts

@@ -178,7 +178,7 @@ export class NodeMaterialConnectionPoint {
      * Gets a boolean indicating that the current point is connected
      */
     public get isConnected(): boolean {
-        return this.connectedPoint !== null || this.isConnectedInFragmentShader || this.isConnectedInVertexShader || this.isConnectedToInputBlock;
+        return this.connectedPoint !== null || this.isConnectedInFragmentShader || this.isConnectedInVertexShader || this.isConnectedToInputBlock || this._endpoints.length > 0;
     }
 
     /**