[421-update-units] Remove Duplicate Menu Entries for Units (Closes #421)

Merging branch '421-update-units'  into 'main'.

See merge request !1283

GUI/View/Main/ActionManager.cpp

@@ -226,20 +226,6 @@ void ActionManager::onAboutToShowSettingsMenu()
 
     m_settingsMenu->addSeparator();
 
-    auto* unitActions = new QActionGroup(this);
-    const auto addUnitAction = [=](const QString& text, bool isAngstrom) {
-        auto* action = m_settingsMenu->addAction(
-            text, [=]() { appSettings->setDefaultUnitIsAngstrom(isAngstrom); });
-        action->setCheckable(true);
-        action->setChecked(appSettings->defaultUnitIsAngstrom() == isAngstrom);
-        unitActions->addAction(action);
-    };
-
-    addUnitAction("Lengths in nanometer", false);
-    addUnitAction(u8"Lengths in \u00c5ngstrom", true);
-
-    m_settingsMenu->addSeparator();
-
     // The dark style is not completed so far. See issue #220
     // The light style is almost done, but with dark system theme it may lead to invisible
     // text. See issue #276

GUI/View/SampleDesigner/SampleForm.cpp

@@ -13,6 +13,7 @@
 //  ************************************************************************************************
 
 #include "GUI/View/SampleDesigner/SampleForm.h"
+#include "GUI/Application/ApplicationSettings.h"
 #include "GUI/Model/Sample/SampleItem.h"
 #include "GUI/Util/ActionFactory.h"
 #include "GUI/View/Common/DoubleSpinBox.h"
@@ -252,6 +253,7 @@ void SampleForm::ensureVisible(QWidget* /*w*/)
 void SampleForm::setUseAngstrom(bool angstrom)
 {
     m_useAngstrom = angstrom;
+    appSettings->setDefaultUnitIsAngstrom(angstrom);
     updateUnits();
 }