diff --git a/src/servers/app/drawing/AccelerantHWInterface.cpp b/src/servers/app/drawing/AccelerantHWInterface.cpp
index 015378a8a3..3bda49c897 100644
--- a/src/servers/app/drawing/AccelerantHWInterface.cpp
+++ b/src/servers/app/drawing/AccelerantHWInterface.cpp
@@ -331,6 +331,7 @@ AccelerantHWInterface::SetMode(const display_mode &mode)
 		// being. The color space conversion is handled in CopyBackToFront()
 
 		delete fBackBuffer;
+		fBackBuffer = NULL;
 
 		// TODO: Above not true anymore for single buffered mode!!!
 		// -> fall back to double buffer for fDisplayMode.space != B_RGB32
diff --git a/src/servers/app/drawing/ViewHWInterface.cpp b/src/servers/app/drawing/ViewHWInterface.cpp
index efc5f98f53..8e5382e847 100644
--- a/src/servers/app/drawing/ViewHWInterface.cpp
+++ b/src/servers/app/drawing/ViewHWInterface.cpp
@@ -398,6 +398,7 @@ ViewHWInterface::SetMode(const display_mode &mode)
 		// free and reallocate the bitmaps while the window is locked, 
 		// so that the view does not accidentally draw a freed bitmap
 		delete fBackBuffer;
+		fBackBuffer = NULL;
 		delete fFrontBuffer;
 
 		// NOTE: backbuffer is always B_RGBA32, this simplifies the