Gui: automatically activate the DlgExpressionInput dialog; fixes #4384

src/Gui/DlgExpressionInput.cpp

@@ -107,7 +107,6 @@ DlgExpressionInput::DlgExpressionInput(const App::ObjectIdentifier & _path,
             this->resize(ui->expression->width()+18,this->height());
     }
     ui->expression->setFocus();
-    ui->expression->activateWindow();
 }
 
 DlgExpressionInput::~DlgExpressionInput()
@@ -268,6 +267,13 @@ void DlgExpressionInput::mousePressEvent(QMouseEvent* ev)
     }
 }
 
+void DlgExpressionInput::show()
+{
+    QDialog::show();
+    this->activateWindow();
+    ui->expression->selectAll();
+}
+
 void DlgExpressionInput::showEvent(QShowEvent* ev)
 {
     QDialog::showEvent(ev);

src/Gui/DlgExpressionInput.h

@@ -63,6 +63,9 @@ public:
 
     bool eventFilter(QObject *obj, QEvent *event);
 
+public Q_SLOTS:
+    void show();
+
 protected:
     void showEvent(QShowEvent*);
     void mouseReleaseEvent(QMouseEvent*);