From c94935c7eabfbd5ec93d839ca8f2d85c0486200d Mon Sep 17 00:00:00 2001
From: Joachim Henze <Joachim.Henze@reactos.org>
Date: Tue, 6 Jul 2021 00:49:11 +0200
Subject: [PATCH] [0.4.13][DESK] Fix GetDC/ReleaseDC error management

Fix missing ReleaseDC related to the spectrum (color depth)

We leaked one device context for each bpp change within the
desk.cpl-session, which gave the following logging when closing desk.cpl:
(win32ss/user/ntuser/windc.c:749) err: [00060138] GetDC() without ReleaseDC()!
1 time for each leak.

Partial backport of (#2707)
Fix picked from 0.4.15-dev-2867-g d635ce0cc0336a9b77d243ddce946876f48ec4f6
---
 dll/cpl/desk/settings.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dll/cpl/desk/settings.c b/dll/cpl/desk/settings.c
index c8d4761a05a..dc59fc99008 100644
--- a/dll/cpl/desk/settings.c
+++ b/dll/cpl/desk/settings.c
@@ -472,8 +472,12 @@ OnBPPChanged(IN HWND hwndDlg, IN PSETTINGS_DATA pData)
     /* Show a new spectrum bitmap */
     hSpectrumControl = GetDlgItem(hwndDlg, IDC_SETTINGS_SPECTRUM);
     hSpectrumDC = GetDC(hSpectrumControl);
+    if (hSpectrumDC == NULL)
+        return;
+
     GetClientRect(hSpectrumControl, &client);
     ShowColorSpectrum(hSpectrumDC, &client, dmNewBitsPerPel, pData);
+    ReleaseDC(hSpectrumControl, hSpectrumDC);
 
     /* Find if new parameters are valid */
     Current = pData->CurrentDisplayDevice->CurrentSettings;