Enable Plasma Controls for tab-navigation

src/declarativeimports/plasmacomponents/qml/Button.qml

@@ -120,6 +120,8 @@ Item {
     //     disabled buttons
     opacity: enabled ? 1.0 : 0.5
 
+    activeFocusOnTab: true
+
 
     QtObject {
         id: internal

src/declarativeimports/plasmacomponents/qml/CheckBox.qml

@@ -62,5 +62,7 @@ Private.DualStateButton {
         }
     }
 
+    activeFocusOnTab: true
+
     shadow: Private.ButtonShadow {}
 }

src/declarativeimports/plasmacomponents/qml/RadioButton.qml

@@ -60,6 +60,7 @@ Private.DualStateButton {
             }
         }
     }
+    activeFocusOnTab: true
 
     shadow: Private.RoundShadow {}
 }

src/declarativeimports/plasmacomponents/qml/Slider.qml

@@ -110,6 +110,8 @@ Item {
     //     disabled sliders
     opacity: enabled ? 1.0 : 0.5
 
+    activeFocusOnTab: true
+
     Keys.onUpPressed: {
         if (!enabled || !contents.isVertical)
             return;

src/declarativeimports/plasmacomponents/qml/TextArea.qml

@@ -177,6 +177,8 @@ Item {
      */
     property string placeholderText
 
+    activeFocusOnTab: true
+
     // functions
     /**
      * Copies the currently selected text to the system clipboard.

src/declarativeimports/plasmacomponents/qml/TextField.qml

@@ -171,6 +171,8 @@ FocusScope {
      */
     property alias maximumLength: textInput.maximumLength
 
+    activeFocusOnTab: true
+
     /**
      * Emitted when the text input is accepted.
      */