XCB: Don't trigger less specific shortcuts

Without this patch some keycodes like Ctrl+Shift+= may generate several
similar key sequences like Ctrl++ and + but only more specific keys
should be returned by QXcbKeyboard::possibleKeys.

Task-number: QTBUG-38137
Change-Id: I23f6522eefaa3b83cfa639f76bdc6a19b450c6f9
Reviewed-by: Gatis Paeglis <gatis.paeglis@digia.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/plugins/platforms/xcb/qxcbkeyboard.cpp b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
index fc3443aba5..dae3a79628 100644
--- a/src/plugins/platforms/xcb/qxcbkeyboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
@@ -910,6 +910,18 @@ QList<int> QXcbKeyboard::possibleKeys(const QKeyEvent *event) const
             if (qtKey == baseQtKey || qtKey == 0)
                 continue;
 
+            // catch only more specific shortcuts, i.e. Ctrl+Shift+= also generates Ctrl++ and +,
+            // but Ctrl++ is more specific than +, so we should skip the last one
+            bool ambiguous = false;
+            foreach (int shortcut, result) {
+                if (int(shortcut & ~Qt::KeyboardModifierMask) == qtKey && (shortcut & mods) == mods) {
+                    ambiguous = true;
+                    break;
+                }
+            }
+            if (ambiguous)
+                continue;
+
             result += (qtKey + mods);
         }
     }