Make sure you have no unsaved changes before saving

core/document.cpp

@@ -4558,6 +4558,11 @@ void Document::setHistoryClean(bool clean)
         d->m_undoStack->resetClean();
 }
 
+bool Document::isHistoryClean() const
+{
+    return d->m_undoStack->isClean();
+}
+
 bool Document::canSaveChanges() const
 {
     if (!d->m_generator)

core/document.h

@@ -831,6 +831,8 @@ public:
      */
     void setHistoryClean(bool clean);
 
+    bool isHistoryClean() const;
+
     /**
      * Saving capabilities. Their availability varies according to the
      * underlying generator and/or the document type.

part/pageview.cpp

@@ -4778,6 +4778,11 @@ void PageView::slotSetMouseTableSelect()
 
 void PageView::slotSignature()
 {
+    if (!d->document->isHistoryClean()) {
+        KMessageBox::information(this, i18n("You have unsaved changes. Please save the document before signing it."));
+        return;
+    }
+
     d->messageWindow->display(i18n("Draw a rectangle to insert the signature field"), QString(), PageViewMessage::Info, -1);
 
     if (!d->annotator) {