Solved Issue #3, #2 and fixed an Android 6.0 specific bug, that would prevent the UI from updating when changes to the gameboard were made.

Also corrected the keyboard layout.

app/src/main/res/menu/menu_drawer.xml

@@ -5,17 +5,23 @@
         <item android:id="@+id/menu_reset" android:icon="@android:drawable/ic_menu_delete"
             android:title="@string/menu_reset" />
     </group>
-    <group android:id="@+id/group2">
+    <group android:id="@+id/group4">
         <item android:id="@+id/nav_newgame" android:icon="@android:drawable/ic_menu_today"
             android:title="@string/menu_main" />
+    </group>
+    <group android:id="@+id/group2">
         <item android:id="@+id/nav_highscore" android:icon="@android:drawable/ic_menu_myplaces"
             android:title="@string/menu_highscore" />
+    </group>
+    <group android:id="@+id/group5">
         <item android:id="@+id/menu_settings" android:icon="@android:drawable/ic_menu_manage"
             android:title="@string/menu_settings" />
     </group>
     <group android:id="@+id/group3">
             <item android:id="@+id/menu_help" android:icon="@android:drawable/ic_menu_help"
                 android:title="@string/menu_help" />
+    </group>
+    <group android:id="@+id/group6">
             <item android:id="@+id/menu_about" android:icon="@android:drawable/ic_menu_info_details"
                 android:title="@string/menu_about" />
     </group>

app/src/main/res/menu/menu_drawer_main.xml

@@ -3,12 +3,16 @@
     <group android:id="@+id/group1">
         <item android:id="@+id/nav_highscore_main" android:icon="@android:drawable/ic_menu_myplaces"
             android:title="@string/menu_highscore" />
+    </group>
+    <group android:id="@+id/group2">
         <item android:id="@+id/menu_settings_main" android:icon="@android:drawable/ic_menu_manage"
         android:title="@string/menu_settings" />
     </group>
     <group android:id="@+id/group3">
     <item android:id="@+id/menu_help_main" android:icon="@android:drawable/ic_menu_help"
         android:title="@string/menu_help" />
+    </group>
+    <group android:id="@+id/group4">
     <item android:id="@+id/menu_about_main" android:icon="@android:drawable/ic_menu_info_details"
         android:title="@string/menu_about" />
     </group>

app/src/main/res/values-de/strings.xml

@@ -23,7 +23,7 @@
     <string name="difficulty_moderate">Normal</string>
     <string name="difficulty_hard">Schwer</string>
     <string name="about_qqwing">Diese App benutzt eine modifizierte Version des QQWing v1.3.4.</string>
-    <string name="average_time">&#2205; Zeit:</string>
+    <string name="average_time">Durchschnittliche Zeit:</string>
     <string name="cancel">Abbrechen</string>
     <string name="description">eine privacy friendly App</string>
     <string name="gametype_unspecified">Unspezifiziert</string>
@@ -34,7 +34,7 @@
     <string name="hint_usage">Wähle ein gültiges Feld aus und drücke dann auf den Hinweis Knopf um dann das makierte Feld aufzulösen.</string>
     <string name="loadgame_delete_confirmation">Bist du sicher, dass du den Spielstand löschen möchtest?</string>
     <string name="menu_continue_game">Spiel Fortsetzen</string>
-    <string name="menu_reset">Spielfeld zurücksetzen</string>
+    <string name="menu_reset">Zurücksetzen</string>
     <string name="min_time">Beste Zeit:</string>
     <string name="number_of_games">Abgeschlossene Spiele:</string>
     <string name="number_of_hints">Benutzte Hinweise:</string>

app/src/main/res/values/strings.xml

@@ -28,9 +28,7 @@
     <!-- #Highlight -->
     <string name="pref_header_highlight">Highlighting</string>
     <string name="pref_group_highlight_selection">Selection highlight</string>
-    <string name="pref_highlight_rows">Connected rows</string>
+    <string name="pref_highlight_connected">Connected Fields</string>
-    <string name="pref_highlight_cols">Connected columns</string>
-    <string name="pref_highlight_secs">Connected sections</string>
     <string name="pref_group_highlight_value">Value highlight</string>
     <string name="pref_highlight_vals">Same values</string>
     <string name="pref_highlight_notes">Notes</string>
@@ -97,8 +95,6 @@
     <string name="number_of_hints"># used hints:</string>
     <string name="number_of_games"># completed games:</string>
     <string name="total_of_time">Total time played:</string>
-    <string name="average_time">&#2205; time:</string>
-    <string name="min_time">Best time:</string>
     <string name="average_time">average time:</string>
     <string name="min_time">best time:</string>
     <string name="reset_stats">Reset All</string>

app/src/main/res/xml/pref_general.xml

@@ -6,7 +6,6 @@
         android:title="@string/pref_automatic_note_deletion"
         android:summary="@string/pref_automatic_note_deletion_summary"
         android:defaultValue="true"/>
-    </PreferenceCategory>
 
     <ListPreference
         android:key="pref_symbols"
@@ -16,6 +15,27 @@
         android:entryValues="@array/pref_symbols_list_values"
         android:negativeButtonText="@null"
         android:positiveButtonText="@null" />
+    </PreferenceCategory>
+
+    <PreferenceCategory android:title="@string/pref_group_highlight_selection">
+        <SwitchPreference android:id="@+id/pref_highlight_connected"
+            android:key="pref_highlight_connected"
+            android:title="@string/pref_highlight_connected"
+            android:summary=""
+            android:defaultValue="true"/>
+    </PreferenceCategory>
+    <PreferenceCategory android:title="@string/pref_group_highlight_value">
+        <SwitchPreference android:id="@+id/pref_highlight_vals"
+            android:key="pref_highlight_vals"
+            android:title="@string/pref_highlight_vals"
+            android:summary=""
+            android:defaultValue="true"/>
+        <SwitchPreference android:id="@+id/pref_highlight_notes"
+            android:key="pref_highlight_notes"
+            android:title="@string/pref_highlight_notes"
+            android:summary=""
+            android:defaultValue="true"/>
+    </PreferenceCategory>
 
     <!-- NOTE: EditTextPreference accepts EditText attributes. -->
     <!-- NOTE: EditTextPreference's summary should be set to its value by the activity code. -->