From 72c800821829bba467746e0347c830b35f0fa35f Mon Sep 17 00:00:00 2001
From: Levi Jetzer <levi.jetzer@ibsys.ch>
Date: Thu, 6 Aug 2026 17:20:48 +0200
Subject: [PATCH] Avoid needless dock churn in
 QETElementEditor::updateInformations()

updateInformations() runs on every selection change and on every undo
stack index change. It unconditionally called clearToolsDock(), which
removes and hides the current editor widget, and then re-inserted the
same widget into the stack. When the editor for the new selection is
the one already shown, that means removing, hiding, reparenting and
re-adding a widget only to end up in the same state.

Look up the editor first and only clear and re-insert the tools dock
when a different editor is needed. setPart()/setParts() still updates
the contents in every case, so the visible result is unchanged.
---
 sources/editor/ui/qetelementeditor.cpp | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/sources/editor/ui/qetelementeditor.cpp b/sources/editor/ui/qetelementeditor.cpp
index 9a4eb2ffb..691b370fd 100644
--- a/sources/editor/ui/qetelementeditor.cpp
+++ b/sources/editor/ui/qetelementeditor.cpp
@@ -573,9 +573,11 @@ void QETElementEditor::updateInformations()
 			|| selection_xml_name == "ellipse"
 			|| selection_xml_name == "arc")
 		{
-			clearToolsDock();
 			//We add the editor widget
 			ElementItemEditor *editor = static_cast<ElementItemEditor*>(m_editors[selection_xml_name]);
+			if (m_tools_dock_stack -> widget(1) != editor) {
+				clearToolsDock();
+			}
 
 #if TODO_LIST
 #pragma message("@TODO Check if it takes longer than setting the parts again to the editor.")
@@ -608,7 +610,9 @@ void QETElementEditor::updateInformations()
 					success = editor -> setParts(cep_list);
 				}
 				if (success) {
-					m_tools_dock_stack -> insertWidget(1, editor);
+					if (m_tools_dock_stack -> widget(1) != editor) {
+						m_tools_dock_stack -> insertWidget(1, editor);
+					}
 					m_tools_dock_stack -> setCurrentIndex(1);
 				}
 				else {
@@ -626,8 +630,10 @@ void QETElementEditor::updateInformations()
 			// multi edit for polygons makes no sense
 			// TODO: maybe allowing multipart edit when number of points is the same?
 			//We add the editor widget
-			clearToolsDock();
 			ElementItemEditor *editor = static_cast<ElementItemEditor*>(m_editors[selection_xml_name]);
+			if (m_tools_dock_stack -> widget(1) != editor) {
+				clearToolsDock();
+			}
 			CustomElementPart* part = editor -> currentPart();
 			bool equal = part == cep_list.first();
 
@@ -637,7 +643,9 @@ void QETElementEditor::updateInformations()
 					success = editor -> setPart(cep_list.first());
 				}
 				if (success) {
-					m_tools_dock_stack -> insertWidget(1, editor);
+					if (m_tools_dock_stack -> widget(1) != editor) {
+						m_tools_dock_stack -> insertWidget(1, editor);
+					}
 					m_tools_dock_stack -> setCurrentIndex(1);
 				}
 				else {
@@ -655,11 +663,15 @@ void QETElementEditor::updateInformations()
 
 	//There's several parts selecteds and all can be edited by style editor.
 	if (style_editable) {
-		clearToolsDock();
 		ElementItemEditor *selection_editor = m_editors["style"];
+		if (m_tools_dock_stack -> widget(1) != selection_editor) {
+			clearToolsDock();
+		}
 		if (selection_editor) {
 			if (selection_editor -> setParts(cep_list)) {
-				m_tools_dock_stack -> insertWidget(1, selection_editor);
+				if (m_tools_dock_stack -> widget(1) != selection_editor) {
+					m_tools_dock_stack -> insertWidget(1, selection_editor);
+				}
 				m_tools_dock_stack -> setCurrentIndex(1);
 			}
 			else {