add empty parameters list constructor support to all widgets - for future usage by factory methods

src/dlangui/dialogs/filedlg.d

@@ -314,3 +314,7 @@ class FileDialog : Dialog, CustomGridCellAdapter {
         _fileList.setFocus();
     }
 }
+
+
+class FilePathPanel : FrameLayout {
+}

src/dlangui/graphics/ftfonts.d

@@ -205,6 +205,8 @@ private class FreeTypeFontFile {
             case 0x2039:
                 return '<';
             case 0x203A:
+            case '‣':
+            case '►':
                 return '>';
             case 0x2044:
                 return '/';

src/dlangui/widgets/combobox.d

@@ -139,6 +139,11 @@ class ComboBox : ComboBoxBase {
     protected StringListAdapter _adapter;
     protected EditLine _edit;
 
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID) {
         super(ID, (_adapter = new StringListAdapter()), true);
     }

src/dlangui/widgets/controls.d

@@ -344,33 +344,40 @@ class Button : Widget {
     override @property Widget text(dstring s) { _text = s; requestLayout(); return this; }
     override @property Widget text(UIString s) { _text = s; requestLayout(); return this; }
     @property Widget textResource(string s) { _text = s; requestLayout(); return this; }
-    this(string ID = null) {
-		super(ID);
+    /// empty parameter list constructor - for usage by factory
+    this() {
+		super(null);
+        init(UIString());
+    }
+
+    private void init(UIString label) {
         styleId = "BUTTON";
+        _text = label;
 		clickable = true;
         focusable = true;
         trackHover = true;
     }
+
+    /// create with ID parameter
+    this(string ID) {
+		super(ID);
+        init(UIString());
+    }
+    this(string ID, UIString label) {
+		super(ID);
+        init(label);
+    }
     this(string ID, dstring label) {
 		super(ID);
-        _text = label;
-        styleId = "BUTTON";
-		clickable = true;
-        focusable = true;
-        trackHover = true;
+        init(UIString(label));
     }
     this(string ID, string labelResourceId) {
 		super(ID);
-        _text = labelResourceId;
-        styleId = "BUTTON";
-		clickable = true;
-        focusable = true;
-        trackHover = true;
+        init(UIString(labelResourceId));
     }
     /// constructor from action
     this(const Action a) {
-        this("button-action" ~ to!string(a.id));
-        _text = a.labelValue;
+        this("button-action" ~ to!string(a.id), a.labelValue);
         action = a;
     }
 
@@ -408,6 +415,7 @@ class AbstractSlider : WidgetGroup {
     protected int _pageSize = 30;
     protected int _position = 20;
 
+    /// create with ID parameter
     this(string ID) {
         super(ID);
     }
@@ -656,7 +664,12 @@ class ScrollBar : AbstractSlider, OnClickHandler {
         return this; 
     }
 
-    this(string ID = null, Orientation orient = Orientation.Vertical) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null, Orientation.Vertical);
+    }
+    /// create with ID parameter
+    this(string ID, Orientation orient = Orientation.Vertical) {
 		super(ID);
         styleId = "SCROLLBAR";
         _orientation = orient;

src/dlangui/widgets/editors.d

@@ -1712,6 +1712,11 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
 /// single line editor
 class EditLine : EditWidgetBase {
 
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID, dstring initialContent = null) {
         super(ID, ScrollBarMode.Invisible, ScrollBarMode.Invisible);
         _content = new EditableContent(false);
@@ -1880,6 +1885,11 @@ class EditLine : EditWidgetBase {
 
 /// single line editor
 class EditBox : EditWidgetBase {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID, dstring initialContent = null, ScrollBarMode hscrollbarMode = ScrollBarMode.Visible, ScrollBarMode vscrollbarMode = ScrollBarMode.Visible) {
         super(ID, hscrollbarMode, vscrollbarMode);
         _content = new EditableContent(true); // multiline

src/dlangui/widgets/grid.d

@@ -1163,7 +1163,12 @@ class StringGridWidget : StringGridWidgetBase {
 	protected dstring[] _rowTitles;
 	protected dstring[] _colTitles;
 
-	this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID) {
 		super(ID);
 		styleId = "EDIT_BOX";
 	}

src/dlangui/widgets/layouts.d

@@ -278,7 +278,12 @@ class ResizerWidget : Widget {
     protected string _styleVertical;
     protected string _styleHorizontal;
 
-    this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+    this(string ID) {
         super(ID);
         _styleVertical = "RESIZER_VERTICAL";
         _styleHorizontal = "RESIZER_HORIZONTAL";
@@ -461,7 +466,7 @@ class ResizerWidget : Widget {
 }
 
 
-
+/// Arranges items either vertically or horizontally
 class LinearLayout : WidgetGroup {
     protected Orientation _orientation = Orientation.Vertical;
     /// returns linear layout orientation (Vertical, Horizontal)
@@ -469,7 +474,12 @@ class LinearLayout : WidgetGroup {
     /// sets linear layout orientation
     @property LinearLayout orientation(Orientation value) { _orientation = value; requestLayout(); return this; }
 
-	this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID) {
 		super(ID);
 		_layoutItems = new LayoutItems();
 	}
@@ -523,15 +533,27 @@ class LinearLayout : WidgetGroup {
 
 }
 
+/// Arranges children vertically
 class VerticalLayout : LinearLayout {
-    this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+    this(string ID) {
         super(ID);
         orientation = Orientation.Vertical;
     }
 }
 
+/// Arranges children horizontally
 class HorizontalLayout : LinearLayout {
-    this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+    this(string ID) {
         super(ID);
         orientation = Orientation.Horizontal;
     }
@@ -539,6 +561,11 @@ class HorizontalLayout : LinearLayout {
 
 /// place all children into same place (usually, only one child should be visible at a time)
 class FrameLayout : WidgetGroup {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID) {
         super(ID);
     }

src/dlangui/widgets/lists.d

@@ -298,7 +298,12 @@ class ListWidget : WidgetGroup, OnScrollHandler {
         requestLayout();
     }
 
-	this(string ID = null, Orientation orientation = Orientation.Vertical) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID, Orientation orientation = Orientation.Vertical) {
 		super(ID);
         _orientation = orientation;
         focusable = true;

src/dlangui/widgets/menu.d

@@ -342,8 +342,14 @@ class MenuItemWidget : WidgetGroup {
 		addChild(_label);
 		// accelerator
 		dstring acc = _item.acceleratorText;
-		if (_item.isSubmenu && !mainMenu)
-			acc = "‣"d;
+		if (_item.isSubmenu && !mainMenu) {
+            version (Windows) {
+			    acc = ">"d;
+			    //acc = "►"d;
+            } else {
+			    acc = "‣"d;
+            }
+        }
 		if (acc !is null) {
 			_accel = new TextWidget("MENU_ACCEL");
 			_accel.styleId = "MENU_ACCEL";

src/dlangui/widgets/scroll.d

@@ -304,7 +304,12 @@ class ScrollWidget :  ScrollWidgetBase {
         requestLayout();
         return this;
     }
-	this(string ID = null, ScrollBarMode hscrollbarMode = ScrollBarMode.Visible, ScrollBarMode vscrollbarMode = ScrollBarMode.Visible) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID, ScrollBarMode hscrollbarMode = ScrollBarMode.Visible, ScrollBarMode vscrollbarMode = ScrollBarMode.Visible) {
 		super(ID, hscrollbarMode, vscrollbarMode);
     }
 

src/dlangui/widgets/tabs.d

@@ -177,6 +177,11 @@ class TabControl : WidgetGroup {
 	/// signal of tab change (e.g. by clicking on tab header)
 	Signal!TabHandler onTabChangedListener;
 
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID) {
         super(ID);
         _items = new TabItemList();
@@ -373,6 +378,11 @@ class TabControl : WidgetGroup {
 
 /// container for widgets controlled by TabControl
 class TabHost : FrameLayout, TabHandler {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID, TabControl tabControl = null) {
         super(ID);
         _tabControl = tabControl;
@@ -458,6 +468,11 @@ class TabHost : FrameLayout, TabHandler {
 class TabWidget : VerticalLayout, TabHandler {
     protected TabControl _tabControl;
     protected TabHost _tabHost;
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
     this(string ID) {
         super(ID);
         _tabControl = new TabControl("TAB_CONTROL");

src/dlangui/widgets/tree.d

@@ -549,7 +549,12 @@ class TreeWidgetBase :  ScrollWidget, OnTreeContentChangeListener, OnTreeStateCh
     protected bool _needUpdateWidgets;
     protected bool _needUpdateWidgetStates;
 
-	this(string ID = null, ScrollBarMode hscrollbarMode = ScrollBarMode.Visible, ScrollBarMode vscrollbarMode = ScrollBarMode.Visible) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID, ScrollBarMode hscrollbarMode = ScrollBarMode.Visible, ScrollBarMode vscrollbarMode = ScrollBarMode.Visible) {
 		super(ID, hscrollbarMode, vscrollbarMode);
         contentWidget = new VerticalLayout("TREE_CONTENT");
         _tree = new TreeItems();
@@ -737,7 +742,12 @@ class TreeWidgetBase :  ScrollWidget, OnTreeContentChangeListener, OnTreeStateCh
 
 /// Tree widget with items which can have icons and labels
 class TreeWidget :  TreeWidgetBase {
-	this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID) {
 		super(ID);
     }
 }

src/dlangui/widgets/widget.d

@@ -177,8 +177,12 @@ class Widget {
 	    private static int _instanceCount = 0;
         private static bool _appShuttingDown = false;
     }
-	/// create widget, with optional id
-    this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+    this(string ID) {
 		_id = ID;
         _state = State.Enabled;
 		debug(resalloc) _instanceCount++;
@@ -1327,7 +1331,12 @@ alias WidgetList = ObjectList!Widget;
 /** Base class for widgets which have children. */
 class WidgetGroup : Widget {
 
-	this(string ID = null) {
+    /// empty parameter list constructor - for usage by factory
+    this() {
+        this(null);
+    }
+    /// create with ID parameter
+	this(string ID) {
 		super(ID);
 	}