keysequenceeditor: override backspace and esc behavior

Fixes #1455

app/dialog/preferences/keysequenceeditor.cpp

@@ -21,11 +21,14 @@
 #include "keysequenceeditor.h"
 
 #include <QAction>
+#include <QKeyEvent>
 
 namespace olive {
 
+#define super QKeySequenceEdit
+
 KeySequenceEditor::KeySequenceEditor(QWidget* parent, QAction* a)
-  : QKeySequenceEdit(parent), action(a) {
+  : super(parent), action(a) {
   setKeySequence(action->shortcut());
 }
 
@@ -49,4 +52,26 @@ QString KeySequenceEditor::export_shortcut() {
   return nullptr;
 }
 
+void KeySequenceEditor::keyPressEvent(QKeyEvent *e)
+{
+  if (e->key() == Qt::Key_Backspace) {
+    clear();
+  } else if (e->key() == Qt::Key_Escape) {
+    e->ignore();
+  } else{
+    super::keyPressEvent(e);
+  }
+}
+
+void KeySequenceEditor::keyReleaseEvent(QKeyEvent *e)
+{
+  if (e->key() == Qt::Key_Backspace) {
+    // Do nothing
+  } else if (e->key() == Qt::Key_Escape) {
+    e->ignore();
+  } else {
+    super::keyReleaseEvent(e);
+  }
+}
+
 }

app/dialog/preferences/keysequenceeditor.h

@@ -94,6 +94,12 @@ public:
    * because a default shortcut does not need to be saved to a file.
    */
   QString export_shortcut();
+
+protected:
+  virtual void keyPressEvent(QKeyEvent *e) override;
+
+  virtual void keyReleaseEvent(QKeyEvent *e) override;
+
 private:
   /**
    * @brief Internal reference to the linked QAction