diff -r dee5afe5301f -r 3f74d0d4af4c src/gui/kernel/qkeymapper_x11.cpp
--- a/src/gui/kernel/qkeymapper_x11.cpp	Mon Mar 15 12:43:09 2010 +0200
+++ b/src/gui/kernel/qkeymapper_x11.cpp	Thu Apr 08 14:19:33 2010 +0300
@@ -360,6 +360,13 @@
 
         if (code && code < 0xfffe)
             code = QChar(code).toUpper().unicode();
+
+        if (code == Qt::Key_Tab && (baseModifiers & Qt::ShiftModifier)) {
+            // map shift+tab to shift+backtab
+            code = Qt::Key_Backtab;
+            text = QString();
+        }
+
         if (code == baseCode)
             continue;
 
@@ -448,6 +455,13 @@
 
         if (code && code < 0xfffe)
             code = QChar(code).toUpper().unicode();
+
+        if (code == Qt::Key_Tab && (baseModifiers & Qt::ShiftModifier)) {
+            // map shift+tab to shift+backtab
+            code = Qt::Key_Backtab;
+            text = QString();
+        }
+
         if (code == baseCode)
             continue;
 
@@ -1059,8 +1073,8 @@
     XF86XK_AudioNext,           Qt::Key_MediaNext,
     XF86XK_AudioRecord,         Qt::Key_MediaRecord,
     XF86XK_Mail,                Qt::Key_LaunchMail,
-    XF86XK_MyComputer,          Qt::Key_Launch0,
-    XF86XK_Calculator,          Qt::Key_Calculator,
+    XF86XK_MyComputer,          Qt::Key_Launch0,  // ### Qt 5: remap properly
+    XF86XK_Calculator,          Qt::Key_Launch1,
     XF86XK_Memo,                Qt::Key_Memo,
     XF86XK_ToDoList,            Qt::Key_ToDoList,
     XF86XK_Calendar,            Qt::Key_Calendar,
@@ -1158,7 +1172,7 @@
     XF86XK_Bluetooth,           Qt::Key_Bluetooth,
     XF86XK_Suspend,             Qt::Key_Suspend,
     XF86XK_Hibernate,           Qt::Key_Hibernate,
-    XF86XK_Launch0,             Qt::Key_Launch2,
+    XF86XK_Launch0,             Qt::Key_Launch2, // ### Qt 5: remap properly
     XF86XK_Launch1,             Qt::Key_Launch3,
     XF86XK_Launch2,             Qt::Key_Launch4,
     XF86XK_Launch3,             Qt::Key_Launch5,