diff --git a/src/plugins/platformthemes/gtk3/qgtk3json.cpp b/src/plugins/platformthemes/gtk3/qgtk3json.cpp
index a5af2ae9af8..a517fec63ff 100644
--- a/src/plugins/platformthemes/gtk3/qgtk3json.cpp
+++ b/src/plugins/platformthemes/gtk3/qgtk3json.cpp
@@ -211,6 +211,15 @@ const QJsonDocument QGtk3Json::save(const QGtk3Storage::PaletteMap &map)
                     }
                     break;
 
+                case QGtk3Storage::SourceType::Mixed: {
+                        sourceObject.insert(ceColorGroup, fromColorGroup(s.mix.sourceGroup));
+                        QJsonArray colorRoles;
+                        colorRoles << fromColorRole(s.mix.colorRole1)
+                                   << fromColorRole(s.mix.colorRole2);
+                        sourceObject.insert(ceColorRole, colorRoles);
+                    }
+                    break;
+
                 case QGtk3Storage::SourceType::Invalid:
                     break;
                 }
@@ -387,6 +396,26 @@ bool QGtk3Json::load(QGtk3Storage::PaletteMap &map, const QJsonDocument &doc)
                     }
                     break;
 
+                case QGtk3Storage::SourceType::Mixed: {
+                        if (!sourceObject[ceColorRole].isArray()) {
+                            qCInfo(lcQGtk3Interface) << "Mixed brush missing the array of color roles for palette:" << paletteName
+                                                     << "Brush" << colorRoleName;
+                            return false;
+                        }
+                        QJsonArray colorRoles = sourceObject[ceColorRole].toArray();
+                        if (colorRoles.size() < 2) {
+                            qCInfo(lcQGtk3Interface) << "Mixed brush missing enough color roles for palette" << paletteName
+                                                     << "Brush" << colorRoleName;
+                            return false;
+                        }
+                        const QPalette::ColorRole colorRole1 = toColorRole(colorRoles[0].toString());
+                        const QPalette::ColorRole colorRole2 = toColorRole(colorRoles[1].toString());
+                        GETSTR(sourceObject, ceColorGroup);
+                        const QPalette::ColorGroup sourceGroup = toColorGroup(value);
+                        s = QGtk3Storage::Source(sourceGroup, colorRole1, colorRole2);
+                    }
+                    break;
+
                 case QGtk3Storage::SourceType::Invalid:
                     qInfo(lcQGtk3Interface) << "Invalid source type for palette" << paletteName
                                               << "Brush." << colorRoleName;
diff --git a/src/plugins/platformthemes/gtk3/qgtk3storage.cpp b/src/plugins/platformthemes/gtk3/qgtk3storage.cpp
index 2877b285901..2991212d033 100644
--- a/src/plugins/platformthemes/gtk3/qgtk3storage.cpp
+++ b/src/plugins/platformthemes/gtk3/qgtk3storage.cpp
@@ -75,6 +75,31 @@ QBrush QGtk3Storage::brush(const Source &source, const BrushMap &map) const
         return b;
     }
 
+    case SourceType::Mixed: {
+        // check the mixing source to be valid and be a Gtk source
+        constexpr auto check_source = [](const Source &source) -> bool
+        {
+            return source.isValid() && (source.sourceType == SourceType::Gtk);
+        };
+
+        const Source source1 = brush(TargetBrush(source.mix.sourceGroup,
+                                                 source.mix.colorRole1), map);
+        if (!check_source(source1))
+            return QBrush();
+
+        const Source source2 = brush(TargetBrush(source.mix.sourceGroup,
+                                                 source.mix.colorRole2), map);
+        if (!check_source(source2))
+            return QBrush();
+
+        const QBrush brush2 = brush(source2, map);
+        // the output brush is a copy of the brush from the first source
+        QBrush brush1 = brush(source1, map);
+        // only color is mixed
+        brush1.setColor(MixSources::mixColors(brush1.color(), brush2.color()));
+        return brush1;
+    }
+
     case SourceType::Fixed:
         return source.fix.fixedBrush;
 
@@ -413,6 +438,7 @@ const QGtk3Storage::PaletteMap QGtk3Storage::savePalettes() const
                 break;
             case SourceType::Fixed:
             case SourceType::Modified:
+            case SourceType::Mixed:
             case SourceType::Invalid:
                 break;
             }
@@ -554,10 +580,22 @@ void QGtk3Storage::createMapping()
 
         GTK(button, Foreground, ACTIVE);
         ADD(Inactive, WindowText);
-        LIGHTER(Normal, WindowText, 50);
-        ADD(Disabled, Text);
-        ADD(Disabled, WindowText);
-        ADD(Disabled, ButtonText);
+
+        auto ADD_MIX = [&map](QPalette::ColorGroup targetGroup,
+                              QPalette::ColorRole targetRole,
+                              QPalette::ColorGroup sourceGroup,
+                              QPalette::ColorRole role1,
+                              QPalette::ColorRole role2)
+        {
+            const Source source{sourceGroup, role1, role2};
+            map.insert(TargetBrush(targetGroup, targetRole), source);
+        };
+        ADD_MIX(QPalette::Disabled, QPalette::Text,
+                QPalette::Normal, QPalette::Base, QPalette::Text);
+        ADD_MIX(QPalette::Disabled, QPalette::WindowText,
+                QPalette::Normal, QPalette::Window, QPalette::WindowText);
+        ADD_MIX(QPalette::Disabled, QPalette::ButtonText,
+                QPalette::Normal, QPalette::Button, QPalette::ButtonText);
 
         GTK(button, Text, NORMAL);
         ADD(Inactive, ButtonText);
diff --git a/src/plugins/platformthemes/gtk3/qgtk3storage_p.h b/src/plugins/platformthemes/gtk3/qgtk3storage_p.h
index 45192263a91..cd40ae18e41 100644
--- a/src/plugins/platformthemes/gtk3/qgtk3storage_p.h
+++ b/src/plugins/platformthemes/gtk3/qgtk3storage_p.h
@@ -41,6 +41,7 @@ class QGtk3Storage
         Gtk,
         Fixed,
         Modified,
+        Mixed,
         Invalid
     };
     Q_ENUM(SourceType)
@@ -80,6 +81,27 @@ class QGtk3Storage
         }
     };
 
+    // Mixed source: Populate a brush by mixing two brushes.
+    // Useful for creating disabled color by mixing,
+    // for example the background and foreground colors.
+    struct MixSources {
+        QPalette::ColorGroup sourceGroup; // source group of the mixing color roles
+        QPalette::ColorRole colorRole1;
+        QPalette::ColorRole colorRole2;
+        QDebug operator<<(QDebug dbg)
+        {
+            return dbg << "QGtkStorage::MixSources(sourceGroup=" << sourceGroup
+                       << ", colorRole1=" << colorRole1
+                       << ", colorRole2=" << colorRole2 << ")";
+        }
+        static inline QColor mixColors(const QColor &color1, const QColor &color2)
+        {
+            return QColor{ (color1.red() + color2.red()) / 2,
+                           (color1.green() + color2.green()) / 2,
+                           (color1.blue() + color2.blue()) / 2 };
+        }
+    };
+
     // Fixed source: Populate a brush with fixed values rather than reading GTK
     struct FixedSource  {
         QBrush fixedBrush;
@@ -95,6 +117,7 @@ class QGtk3Storage
         Gtk3Source gtk3;
         RecursiveSource rec;
         FixedSource fix;
+        MixSources mix;
 
         // GTK constructor
         Source(QGtk3Interface::QGtkWidget wtype, QGtk3Interface::QGtkColorSource csource,
@@ -118,7 +141,7 @@ class QGtk3Storage
             rec.lighter = p_lighter;
         }
 
-        // Recursive ocnstructor for color modification
+        // Recursive constructor for color modification
         Source(QPalette::ColorGroup group, QPalette::ColorRole role,
                Qt::ColorScheme scheme, int p_red, int p_green, int p_blue)
                : sourceType(SourceType::Modified)
@@ -145,6 +168,16 @@ class QGtk3Storage
             rec.deltaBlue = p_blue;
         }
 
+        // Mixed constructor for color modification
+        Source(QPalette::ColorGroup sourceGroup,
+               QPalette::ColorRole role1, QPalette::ColorRole role2)
+            : sourceType(SourceType::Mixed)
+        {
+            mix.sourceGroup = sourceGroup;
+            mix.colorRole1 = role1;
+            mix.colorRole2 = role2;
+        }
+
         // Fixed Source constructor
         Source(const QBrush &brush) : sourceType(SourceType::Fixed)
         {