added testHideThis. The test does not fails for CMake, but the printout shows...

added testHideThis. The test does not fails for CMake, but the printout shows that the connections in the CS are wrong

tests/executables_src/testHideThis.cc

+#include <ChimeraTK/ApplicationCore/ApplicationCore.h>
+#include <ChimeraTK/ApplicationCore/TestFacility.h>
+using namespace ChimeraTK;
+
+struct TestApp : public Application {
+  TestApp() : Application("test") {}
+  ~TestApp() override { shutdown(); }
+
+  ControlSystemModule cs;
+
+  // hides itself, and then produces A and B as sub-grops. Works.
+  struct A : public ApplicationModule {
+    using ApplicationModule::ApplicationModule;
+
+    struct : public VariableGroup {
+      using VariableGroup::VariableGroup;
+
+      ScalarPushInput<int> in{this, "input", "", ""};
+    } self{this, "A", ""};
+
+    // the output of A is the input of B
+    struct : public VariableGroup {
+      using VariableGroup::VariableGroup;
+
+      ScalarOutput<int> in{this, "input", "", ""};
+    } b{this, "B", ""};
+
+    void mainLoop() override {
+      b.in = int(self.in);
+      b.in.write();
+    }
+
+  } a{this, "A", "", HierarchyModifier::hideThis};
+
+  // tries to hide itself like A, but fails. We get B/B/input and B/output
+  struct B : public ApplicationModule {
+    using ApplicationModule::ApplicationModule;
+
+    struct : public VariableGroup {
+      using VariableGroup::VariableGroup;
+
+      ScalarPushInput<int> in{this, "input", "", ""};
+    } self{this, "B", ""};
+
+    // the output of B is one level up (global output)
+    ScalarOutput<int> out{this, "output", "", ""};
+
+    void mainLoop() override {
+      out = int(self.in);
+      out.write();
+    }
+
+  } b{this, "B", "", HierarchyModifier::hideThis}; // name it "HiddenB" here and it works
+
+  void defineConnections() override { findTag(".*").connectTo(cs); }
+};
+
+int main() {
+  TestApp t;
+  ChimeraTK::TestFacility testFacility;
+  testFacility.runApplication();
+
+  t.dumpConnections();
+  t.dump();
+}