From 934ac65e9a23091d864df40285dda2a34bdbbeee Mon Sep 17 00:00:00 2001
From: SpomJ <mihail_a_m@mail.ru>
Date: Mon, 18 May 2026 12:47:21 +0300
Subject: [PATCH 1/3] More fundamental fix

Removes layout constraints when child is hidden, reapplies when child
is shown.
---
 src/gui/SubWindow.cpp | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/gui/SubWindow.cpp b/src/gui/SubWindow.cpp
index c107699252a..ceab5e2606b 100644
--- a/src/gui/SubWindow.cpp
+++ b/src/gui/SubWindow.cpp
@@ -169,7 +169,7 @@ void SubWindow::changeEvent( QEvent *event )
 
 void SubWindow::setVisible(bool visible)
 {
-	if (isDetached())
+	if (isDetached() || visible)
 	{
 		// When detached, top-level window is the child widget itself. (This is janky and is best changed at some point.)
 		// For that reason we forward show/hide to the child widget, and don't touch the hidden attached window frame.
@@ -178,11 +178,7 @@ void SubWindow::setVisible(bool visible)
 	else
 	{
 		// When attached, visibility of the actual window is controlled by SubWindow.
-		// SubWindow::hide() when it's already hidden still causes a size recalculation,
-		// if the child widget is hidden it does not get included into the layout, and maximum size is set to 0x0.
-		// There shouldn't be a reason to keep the child widget hidden when the subwindow is attached.
-		// see bug #8292
-		widget()->show();
+		// Nevertheless, the subwindow contents still need to be visible, which is addressed above.
 		QMdiSubWindow::setVisible(visible);
 	}
 }
@@ -617,10 +613,6 @@ bool SubWindow::eventFilter(QObject* obj, QEvent* event)
 
 	switch (event->type())
 	{
-		case QEvent::WindowStateChange:
-			event->accept();
-			return true;
-
 		case QEvent::Close:
 			if (isDetached())
 			{
@@ -649,6 +641,14 @@ bool SubWindow::eventFilter(QObject* obj, QEvent* event)
 				hide();
 			}
 			return QMdiSubWindow::eventFilter(obj, event);
+			
+		case QEvent::Hide:
+			layout()->setSizeConstraint(QLayout::SetNoConstraint);
+			return QMdiSubWindow::eventFilter(obj, event);
+
+		case QEvent::Show:
+			layout()->setSizeConstraint(QLayout::SetMinAndMaxSize);
+			return QMdiSubWindow::eventFilter(obj, event);
 
 		default:
 			return QMdiSubWindow::eventFilter(obj, event);

From 8f51e9595de3165bc4ea530b71c86848e29bd05e Mon Sep 17 00:00:00 2001
From: SpomJ <mihail_a_m@mail.ru>
Date: Tue, 19 May 2026 02:22:01 +0300
Subject: [PATCH 2/3] fix dumb oversight

I didn't fully soft-revert the last fix so this happened. The issue
was that `|| visible` would steal the thing and QMdiSubWindow handler
wouldn't execute which is important for doing pretty much everything
about the window frame.
---
 src/gui/SubWindow.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/gui/SubWindow.cpp b/src/gui/SubWindow.cpp
index ceab5e2606b..c8747021351 100644
--- a/src/gui/SubWindow.cpp
+++ b/src/gui/SubWindow.cpp
@@ -175,7 +175,7 @@ void SubWindow::setVisible(bool visible)
 		// For that reason we forward show/hide to the child widget, and don't touch the hidden attached window frame.
 		widget()->setVisible(visible);
 	}
-	else
+	if (!isDetached())
 	{
 		// When attached, visibility of the actual window is controlled by SubWindow.
 		// Nevertheless, the subwindow contents still need to be visible, which is addressed above.

From 9f714038a85d186063c9db12b9104942f8eb6a87 Mon Sep 17 00:00:00 2001
From: SpomJ <mihail_a_m@mail.ru>
Date: Tue, 19 May 2026 09:57:00 +0300
Subject: [PATCH 3/3] force a resize after layout is reset

---
 src/gui/SubWindow.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/gui/SubWindow.cpp b/src/gui/SubWindow.cpp
index c8747021351..aa5e0a9427d 100644
--- a/src/gui/SubWindow.cpp
+++ b/src/gui/SubWindow.cpp
@@ -648,6 +648,7 @@ bool SubWindow::eventFilter(QObject* obj, QEvent* event)
 
 		case QEvent::Show:
 			layout()->setSizeConstraint(QLayout::SetMinAndMaxSize);
+			resize(widget()->size().addMargins(decorationMargins())); // manually sync the sizes again
 			return QMdiSubWindow::eventFilter(obj, event);
 
 		default: