Core: Fix 'Expression' and 'Vector' editor outhanging the screen (#22426)

* Core: Fix Expression dialog outhanging main window

Expression dialog is now fully shown inside main window, even if opened from model panel positioned on right side. If Model panel is outside main window, dialog is opened over this panel.

* Core: Fix Vectors dialog outhanging main window

Vectors dialog is now fully shown inside main window, even if opened from model panel positioned on right side. If Model panel is outside main window, dialog is opened over this panel.

* Core: Simplify 'adjustDialogPosition()'

Change suggested and authored by @hyarion

src/Gui/QuantitySpinBox.cpp

@@ -52,6 +52,7 @@
 #include "Command.h"
 #include "Dialogs/DlgExpressionInput.h"
 #include "Tools.h"
+#include "Widgets.h"
 
 
 using namespace Gui;
@@ -618,6 +619,7 @@ void QuantitySpinBox::openFormulaDialog()
     QPoint pos = mapToGlobal(QPoint(0,0));
     box->move(pos-box->expressionPosition());
     box->setExpressionInputSize(width(), height());
+    Gui::adjustDialogPosition(box);
 
     Q_EMIT showFormulaDialog(true);
 }

src/Gui/SpinBox.cpp

@@ -40,6 +40,7 @@
 #include "Command.h"
 #include "Dialogs/DlgExpressionInput.h"
 #include "QuantitySpinBox_p.h"
+#include "Widgets.h"
 
 
 using namespace Gui;
@@ -206,6 +207,7 @@ void ExpressionSpinBox::openFormulaDialog()
     QPoint pos = spinbox->mapToGlobal(QPoint(0,0));
     box->move(pos-box->expressionPosition());
     box->setExpressionInputSize(spinbox->width(), spinbox->height());
+    Gui::adjustDialogPosition(box);
 }
 
 bool ExpressionSpinBox::handleKeyEvent(const QString& text)

src/Gui/Widgets.cpp

@@ -55,6 +55,7 @@
 #include "QuantitySpinBox_p.h"
 #include "Tools.h"
 #include "Dialogs/ui_DlgTreeWidget.h"
+#include "MainWindow.h"
 
 using namespace Gui;
 using namespace App;
@@ -1606,6 +1607,7 @@ void ExpLineEdit::openFormulaDialog()
     QPoint pos = mapToGlobal(QPoint(0,0));
     box->move(pos-box->expressionPosition());
     box->setExpressionInputSize(width(), height());
+    Gui::adjustDialogPosition(box);
 }
 
 void ExpLineEdit::finishFormulaDialog()
@@ -1663,5 +1665,54 @@ bool ButtonGroup::exclusive() const
     return _exclusive;
 }
 
+namespace Gui {
+
+void adjustDialogPosition(QDialog* dialog) {
+    if (!dialog) {
+        return;
+    }
+    const MainWindow* mw = getMainWindow();
+    if (!mw) {
+        return;
+    }
+    
+    dialog->adjustSize(); // ensure correct size
+
+    const QRect mainWindowRect{ mw->mapToGlobal(QPoint(0, 0)), mw->size() };
+    const QRect dialogRect{ dialog->frameGeometry() };
+
+    const bool isFullyInside = mainWindowRect.contains(dialogRect);
+    if (isFullyInside) {
+        return;
+    }
+
+    const bool isCompletelyOutside = !mainWindowRect.intersects(dialogRect);
+    if (isCompletelyOutside) {
+        return;
+    }
+
+    const int margin = 5;
+    const QRect availableArea = mainWindowRect.adjusted(
+        margin, margin, -margin, -margin
+    );
+
+    QPoint adjustedTopLeft = dialogRect.topLeft();
+
+    adjustedTopLeft.setX(std::clamp(
+        adjustedTopLeft.x(),
+        availableArea.left(),
+        availableArea.right() - dialogRect.width()
+    ));
+
+    adjustedTopLeft.setY(std::clamp(
+        adjustedTopLeft.y(),
+        availableArea.top(),
+        availableArea.bottom() - dialogRect.height()
+    ));
+
+    dialog->move(adjustedTopLeft);
+}
+
+}
 
 #include "moc_Widgets.cpp"

src/Gui/Widgets.h

@@ -613,6 +613,15 @@ private:
     bool _exclusive;
 };
 
+/**
+ * Adjusts the position of the given dialog to ensure it remains within the bounds of the main window.
+ * This helps prevent dialogs from appearing partially or fully off-screen relative to the main application window.
+ * 
+ * This function shall be invoked after the dialog has been shown (using show()) or its position or size has changed.
+ * Exception: If the dialog is modal, this function should be called before the dialog is called with exec().
+ */
+void adjustDialogPosition(QDialog* dialog);
+
 } // namespace Gui
 
 #endif // GUI_WIDGETS_H

src/Gui/propertyeditor/PropertyItem.cpp

@@ -1645,6 +1645,7 @@ void VectorListWidget::buttonClicked()
         setValue(data);
     });
 
+    Gui::adjustDialogPosition(dlg);
     dlg->exec();
 }