diff --git a/src/ktooltipwidget.cpp b/src/ktooltipwidget.cpp
--- a/src/ktooltipwidget.cpp
+++ b/src/ktooltipwidget.cpp
@@ -119,15 +119,16 @@
     // It must be assured that:
     // - the content is fully visible
     // - the content is not drawn inside rect
-
-    const QSize size = content->sizeHint();
-    const int margin = q->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth);
+    q->adjustSize();
+    const QSize size = q->sizeHint();
     const QRect screenGeometry = screen->geometry();
-
+    const int margin = q->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth);
+    
     const bool hasRoomToLeft  = (rect.left()   - size.width()  - margin >= screenGeometry.left());
     const bool hasRoomToRight = (rect.right()  + size.width()  + margin <= screenGeometry.right());
     const bool hasRoomAbove   = (rect.top()    - size.height() - margin >= screenGeometry.top());
     const bool hasRoomBelow   = (rect.bottom() + size.height() + margin <= screenGeometry.bottom());
+    
     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
         return QPoint();
     }
@@ -137,12 +138,13 @@
     if (hasRoomBelow || hasRoomAbove) {
         x = qMax(screenGeometry.left(), rect.center().x() - size.width() / 2);
         if (x + size.width() >= screenGeometry.right()) {
-            x = screenGeometry.right() - size.width() + 1;
+            // Disallow negative x. Happens when rect is wider than screen.
+            x = qMax(screenGeometry.left(), screenGeometry.right() - size.width() + 1);
         }
         if (hasRoomBelow) {
             y = rect.bottom() + margin;
         } else {
-            y = rect.top() - size.height() - margin;
+            y = rect.top() - size.height() + margin;
         }
     } else {
         Q_ASSERT(hasRoomToLeft || hasRoomToRight);