Fix webview position upon DragEnter event with QT WebEngine (#536)

* Fix webview position upon DragEnter event with QT WebEngine

* Fix unneeded nesting and missing comment

Author: HITOA

distrho/extra/WebViewImpl.cpp

@@ -1069,6 +1069,7 @@ struct QEvent {
     uint8_t _[SIZEOF_QEvent];
     enum Type {
         Close = 19,
+        DragEnter = 60,
         ContextMenu = 82,
         User = 1000,
     };
@@ -1850,6 +1851,15 @@ class WebViewEventFilter : public QWebChannelAbstractTransport
             return true;
         }
 
+        // HACK forcing webview window position to update, needed for drop area
+        if (type == QEvent::DragEnter && _winId != 0) {
+            XWindowAttributes attrs;
+            XGetWindowAttributes(_display, _winId, &attrs);
+            XMoveWindow(_display, _winId, attrs.x + 1, attrs.y);
+            XMoveWindow(_display, _winId, attrs.x, attrs.y);
+            XFlush(_display);
+        }
+
         if (type == QEvent::Close && watched != nullptr && watched == reinterpret_cast<QObject*>(_devToolsView))
             _devToolsView = nullptr;