gui: fix PixelWidget hotkeys

Change-Id: Iec6097ad518c74397875d76bcd387e4d81e0cca8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/apitrace/+/2224550
Reviewed-by: Po-Hsien Wang <pwang@chromium.org>
Commit-Queue: Robert Tarasov <tutankhamen@chromium.org>
Tested-by: Robert Tarasov <tutankhamen@chromium.org>
diff --git a/gui/pixelwidget.cpp b/gui/pixelwidget.cpp
index 5a25c8e..5440e1e 100644
--- a/gui/pixelwidget.cpp
+++ b/gui/pixelwidget.cpp
@@ -65,6 +65,7 @@
 {
     setWindowTitle(QLatin1String("PixelTool"));
     setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
+    setFocusPolicy(Qt::StrongFocus);
 
     m_gridSize = 1;
     m_gridActive = 0;