Fixed: selection did not work in Cappuccino when doing a right click or dragging

Previously, the selection of a textField did not work as expected when the user did a right click or a drag even if the label was set to none selectable.
Now, with the css style user-select, a textField can only be selected if it is selectable and enable.

Credit to @primalmotion

AppKit/CPTextField.j

@@ -432,6 +432,8 @@ CPTextFieldStatePlaceholder = CPThemeState("placeholder");
     // We only allow first responder status if the field is enabled.
     if (!shouldBeEnabled && [[self window] firstResponder] === self)
         [[self window] makeFirstResponder:nil];
+
+    [self _setCSSSelectionStyleForDOMElement];
 }
 
 /*!
@@ -441,6 +443,7 @@ CPTextFieldStatePlaceholder = CPThemeState("placeholder");
 - (void)setSelectable:(BOOL)aFlag
 {
     _isSelectable = aFlag;
+    [self _setCSSSelectionStyleForDOMElement];
 }
 
 /*!
@@ -700,6 +703,20 @@ CPTextFieldStatePlaceholder = CPThemeState("placeholder");
     return YES;
 }
 
+/*!
+    Set the selection css style for the DOM element of the textField
+    @ignore
+*/
+- (void)_setCSSSelectionStyleForDOMElement
+{
+#if PLATFORM (DOM)
+    if (_isSelectable && [self isEnabled])
+        _DOMElement.style[CPBrowserStyleProperty(@"user-select")] = @"text";
+    else
+        _DOMElement.style[CPBrowserStyleProperty(@"user-select")] = @"none";
+#endif
+}
+
 /*!
     Set the css style for the input element of the textField
     @ignore

AppKit/Platform/DOM/CPPlatformWindow+DOM.j

@@ -365,6 +365,7 @@ _CPPlatformWindowWillCloseNotification = @"_CPPlatformWindowWillCloseNotificatio
         _DOMBodyElement.style["-khtml-user-select"] = "none";
 
     _DOMBodyElement.webkitTouchCallout = "none";
+    _DOMBodyElement.style[CPBrowserStyleProperty(@"user-select")] = @"none";
 
     [self createDOMElements];
     [self _addLayers];