Add indeterminate and disabled states to checkbox for dark theme

ApplicationCode/Resources/ResInsight.qrc

@@ -205,6 +205,10 @@
         <file>themes/dark/arrow-up.svg</file>
         <file>themes/dark/checkbox-unchecked-20x20.png</file>
         <file>themes/dark/checkbox-checked-20x20.png</file>
+        <file>themes/dark/checkbox-indeterminate-20x20.png</file>
+        <file>themes/dark/checkbox-unchecked-disabled-20x20.png</file>
+        <file>themes/dark/checkbox-checked-disabled-20x20.png</file>
+        <file>themes/dark/checkbox-indeterminate-disabled-20x20.png</file>
         <file>SummaryCase24x24.png</file>
     </qresource>
     <qresource prefix="/Shader">

ApplicationCode/Resources/themes/dark.qss

@@ -35,6 +35,29 @@ QCheckBox::indicator:checked
     background-color: $backgroundColor1;
     image: url(:/themes/dark/checkbox-checked-20x20.png);
 }
+QCheckBox::indicator:indeterminate
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-indeterminate-20x20.png);
+}
+
+QCheckBox::indicator:unchecked:disabled
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-unchecked-disabled-20x20.png);
+}
+
+QCheckBox::indicator:checked:disabled
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-checked-disabled-20x20.png);
+}
+
+QCheckBox::indicator:indeterminate:disabled
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-indeterminate-disabled-20x20.png);
+}
 
 QwtPlot["*"]::grid["*"] {
     color: $backgroundColor2;
@@ -175,6 +198,30 @@ QTreeView::indicator:checked
     image: url(:/themes/dark/checkbox-checked-20x20.png);
 }
 
+QTreeView::indicator:indeterminate
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-indeterminate-20x20.png);
+}
+
+QTreeView::indicator:unchecked:disabled
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-unchecked-disabled-20x20.png);
+}
+
+QTreeView::indicator:checked:disabled
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-checked-disabled-20x20.png);
+}
+
+QTreeView::indicator:indeterminate:disabled
+{
+    background-color: $backgroundColor1;
+    image: url(:/themes/dark/checkbox-indeterminate-disabled-20x20.png);
+}
+
 QDockWidget {
     background-color: $mainBackgroundColor;
     titlebar-close-icon:  url(:/themes/dark/blank.svg);