Fix #645, fix #673 (#674)

* fix #645, fix #673

Fix #673 where the function `renameTab(string ID, dstring name)` in `src/dlangui/widgets/tabs.d` failed to find the tab with the given id because it uses the `TabControl`'s own id due to the misuse of lower/upper case names. Changed the function's argument `ID` that have never been used to `id`.  
  
Fix #645 where `EditWidgetBase` doesn't scroll when mouse selection is active and the cursor goes beyond the widget boundaries. Now it scrolls.  
Additionally, added new type of `EditorActions` to make 2 different types of `EditorActions.ScrollLineUp/Down`. The old `ScrollLineUp/Down` made 3 lines scrolling and it doesn't work well with new mouse selection scrolling when out of bounds (scrolls too fast). So now there are `ScrollLineUp/DownSingle` and `ScrollLineUp/DownTriple`. The single one is used by the mouse selection scrolling, the triple one used in all other cases just like before.

* Original ScrollLineUp + ScrollLineUpSingle

src/dlangui/widgets/editors.d

@@ -180,8 +180,12 @@ enum EditorActions : int {
     // Scroll operations
 
     /// Scroll one line up (not changing cursor)
-    ScrollLineUp,
+    ScrollLineUpSingle,
     /// Scroll one line down (not changing cursor)
+    ScrollLineDownSingle,
+    /// Scroll three lines up (not changing cursor)
+    ScrollLineUp,
+    /// Scroll three lines down (not changing cursor)
     ScrollLineDown,
     /// Scroll one page up (not changing cursor)
     ScrollPageUp,
@@ -817,8 +821,8 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
             new Action(EditorActions.DocumentEnd, KeyCode.END, KeyFlag.Control, ActionStateUpdateFlag.never),
             new Action(EditorActions.SelectDocumentEnd, KeyCode.END, KeyFlag.Control | KeyFlag.Shift, ActionStateUpdateFlag.never),
 
-            new Action(EditorActions.ScrollLineUp, KeyCode.UP, KeyFlag.Control, ActionStateUpdateFlag.never),
-            new Action(EditorActions.ScrollLineDown, KeyCode.DOWN, KeyFlag.Control, ActionStateUpdateFlag.never),
+            new Action(EditorActions.ScrollLineUpSingle, KeyCode.UP, KeyFlag.Control, ActionStateUpdateFlag.never),
+            new Action(EditorActions.ScrollLineDownSingle, KeyCode.DOWN, KeyFlag.Control, ActionStateUpdateFlag.never),
 
             // Backspace/Del
             new Action(EditorActions.DelPrevChar, KeyCode.BACK, 0, ActionStateUpdateFlag.never),
@@ -2205,6 +2209,12 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
         }
         if (event.action == MouseAction.Move && (event.flags & MouseButton.Left) != 0) {
             updateCaretPositionByMouse(event.x - _clientRect.left, event.y - _clientRect.top, true);
+            if (event.y < _clientRect.top) {
+                handleAction(new Action(EditorActions.ScrollLineUpSingle));
+            }
+            else if (event.y > _clientRect.bottom) {
+                handleAction(new Action(EditorActions.ScrollLineDownSingle));
+            }
             return true;
         }
         if (event.action == MouseAction.Move && event.flags == 0) {
@@ -2917,9 +2927,9 @@ class EditBox : EditWidgetBase {
         } else if (event.action == ScrollAction.PageDown) {
             dispatchAction(new Action(EditorActions.ScrollPageDown));
         } else if (event.action == ScrollAction.LineUp) {
-            dispatchAction(new Action(EditorActions.ScrollLineUp));
+            dispatchAction(new Action(EditorActions.ScrollLineUpSingle));
         } else if (event.action == ScrollAction.LineDown) {
-            dispatchAction(new Action(EditorActions.ScrollLineDown));
+            dispatchAction(new Action(EditorActions.ScrollLineDownSingle));
         }
         return true;
     }
@@ -3240,6 +3250,18 @@ class EditBox : EditWidgetBase {
                     }
                 }
                 return true;
+            case ScrollLineUpSingle:
+                {
+                    if (_firstVisibleLine > 0) {
+                        _firstVisibleLine -= 1;
+                        if (_firstVisibleLine < 0)
+                            _firstVisibleLine = 0;
+                        measureVisibleText();
+                        updateScrollBars();
+                        invalidate();
+                    }
+                }
+                return true;
             case ScrollPageUp:
                 {
                     int fullLines = _clientRect.height / _lineHeight;
@@ -3268,6 +3290,21 @@ class EditBox : EditWidgetBase {
                     }
                 }
                 return true;
+            case ScrollLineDownSingle:
+                {
+                    int fullLines = _clientRect.height / _lineHeight;
+                    if (_firstVisibleLine + fullLines < _content.length) {
+                        _firstVisibleLine += 1;
+                        if (_firstVisibleLine > _content.length - fullLines)
+                            _firstVisibleLine = _content.length - fullLines;
+                        if (_firstVisibleLine < 0)
+                            _firstVisibleLine = 0;
+                        measureVisibleText();
+                        updateScrollBars();
+                        invalidate();
+                    }
+                }
+                return true;
             case ScrollPageDown:
                 {
                     int fullLines = _clientRect.height / _lineHeight;

src/dlangui/widgets/tabs.d

@@ -475,7 +475,7 @@ class TabControl : WidgetGroupDefaultDrawing {
     }
 
     /// change name of tab
-    void renameTab(string ID, dstring name) {
+    void renameTab(string id, dstring name) {
         int index = _items.indexById(id);
         if (index >= 0) {
             renameTab(index, name);