6 files changed, 9 insertions, 5 deletions
diff --git a/application/palemoon/themes/linux/browser.css b/application/palemoon/themes/linux/browser.css
index 933067c2b..01b3f5c9e 100644
--- a/application/palemoon/themes/linux/browser.css
+++ b/application/palemoon/themes/linux/browser.css
@@ -1608,7 +1608,7 @@ richlistitem[type~="action"][actiontype="switchtab"] > .ac-url-box > .ac-action-
 }
 
 /* When the tab bar is collapsed, show a 1px border in its place. */
-#TabsToolbar[collapsed="true"] {
+#TabsToolbar[tabsontop="false"][collapsed="true"] {
   visibility: visible;
   height: 1px;
   border-bottom-width: 1px;
diff --git a/application/palemoon/themes/osx/browser.css b/application/palemoon/themes/osx/browser.css
index 20e8c5eac..6d0d92015 100644
--- a/application/palemoon/themes/osx/browser.css
+++ b/application/palemoon/themes/osx/browser.css
@@ -1631,7 +1631,7 @@ richlistitem[type~="action"][actiontype="switchtab"][selected="true"] > .ac-url-
 }
 
 /* When the tab bar is collapsed, show a 1px border in its place. */
-#TabsToolbar[collapsed="true"] {
+#TabsToolbar[tabsontop="false"][collapsed="true"] {
   visibility: visible;
   height: 1px;
   border-bottom-width: 1px;
diff --git a/application/palemoon/themes/windows/browser.css b/application/palemoon/themes/windows/browser.css
index aae36c539..9f32b59cf 100644
--- a/application/palemoon/themes/windows/browser.css
+++ b/application/palemoon/themes/windows/browser.css
@@ -1844,7 +1844,7 @@ richlistitem[type~="action"][actiontype="switchtab"] > .ac-url-box > .ac-action-
 }
 
 /* When the tab bar is collapsed, show a 1px border in its place. */
-#TabsToolbar[collapsed="true"] {
+#TabsToolbar[tabsontop="false"][collapsed="true"] {
   visibility: visible;
   height: 1px;
   border-bottom-width: 1px;
diff --git a/gfx/2d/2D.h b/gfx/2d/2D.h
index c1fba3463..e2020dc9e 100644
--- a/gfx/2d/2D.h
+++ b/gfx/2d/2D.h
@@ -488,6 +488,9 @@ public:
   /**
    * Returns a DataSourceSurface with the same data as this one, but
    * guaranteed to have surface->GetType() == SurfaceType::DATA.
+   *
+   * The returning surface might be null, because of OOM or gfx device reset.
+   * The caller needs to do null-check before using it.
    */
   virtual already_AddRefed<DataSourceSurface> GetDataSurface() override;
 
diff --git a/layout/svg/nsSVGMaskFrame.cpp b/layout/svg/nsSVGMaskFrame.cpp
index b8e4b32ae..a22833d61 100644
--- a/layout/svg/nsSVGMaskFrame.cpp
+++ b/layout/svg/nsSVGMaskFrame.cpp
@@ -274,7 +274,8 @@ nsSVGMaskFrame::GetMaskForMaskedFrame(gfxContext* aContext,
   }
   RefPtr<DataSourceSurface> maskSurface = maskSnapshot->GetDataSurface();
   DataSourceSurface::MappedSurface map;
-  if (!maskSurface->Map(DataSourceSurface::MapType::READ, &map)) {
+  if (!maskSurface ||
+      !maskSurface->Map(DataSourceSurface::MapType::READ, &map)) {
     return nullptr;
   }
 
diff --git a/layout/svg/nsSVGUtils.cpp b/layout/svg/nsSVGUtils.cpp
index 0bded21ff..b8794a05d 100644
--- a/layout/svg/nsSVGUtils.cpp
+++ b/layout/svg/nsSVGUtils.cpp
@@ -685,7 +685,7 @@ nsSVGUtils::PaintFrameWithEffects(nsIFrame *aFrame,
   bool isOK = effectProperties.HasNoFilterOrHasValidFilter();
   nsSVGClipPathFrame *clipPathFrame = effectProperties.GetClipPathFrame(&isOK);
   nsSVGMaskFrame *maskFrame = effectProperties.GetFirstMaskFrame(&isOK);
-  if (!isOK) {
+  if (!isOK || !maskFrame) {
     // Some resource is invalid. We shouldn't paint anything.
     return DrawResult::SUCCESS;
   }