diff --git a/client/CMakeLists.txt b/client/CMakeLists.txt
index ed46062e..eed63329 100644
--- a/client/CMakeLists.txt
+++ b/client/CMakeLists.txt
@@ -1,6 +1,11 @@
 cmake_minimum_required(VERSION 3.20)
 project(looking-glass-client C CXX)
 
+if(WIN32)
+  set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS
+    "${PROJECT_SOURCE_DIR}/cmake/vcpkg-triplets/x64-windows-lg.cmake")
+endif()
+
 get_filename_component(PROJECT_TOP "${PROJECT_SOURCE_DIR}/.." ABSOLUTE)
 
 if(PROJECT_SOURCE_DIR STREQUAL PROJECT_BINARY_DIR)
diff --git a/client/cmake/vcpkg-triplets/x64-windows-lg.cmake b/client/cmake/vcpkg-triplets/x64-windows-lg.cmake
index eb8d8a6a..d82654ef 100644
--- a/client/cmake/vcpkg-triplets/x64-windows-lg.cmake
+++ b/client/cmake/vcpkg-triplets/x64-windows-lg.cmake
@@ -7,3 +7,13 @@ if(PORT STREQUAL "openssl")
 else()
   set(VCPKG_LIBRARY_LINKAGE dynamic)
 endif()
+
+if(PORT STREQUAL "angle")
+  # ANGLE's D3D state cache is shared across contexts. Serialize access and
+  # dirty cached state whenever calls switch between shared contexts.
+  string(CONCAT ANGLE_CONTEXT_FLAGS
+    " /DANGLE_ENABLE_SHARE_CONTEXT_LOCK=1"
+    " /DANGLE_FORCE_CONTEXT_CHECK_EVERY_CALL=1")
+  string(APPEND VCPKG_C_FLAGS   "${ANGLE_CONTEXT_FLAGS}")
+  string(APPEND VCPKG_CXX_FLAGS "${ANGLE_CONTEXT_FLAGS}")
+endif()
diff --git a/client/transports/Network/video/shaders.h b/client/transports/Network/video/shaders.h
index 4598eba5..5512d86b 100644
--- a/client/transports/Network/video/shaders.h
+++ b/client/transports/Network/video/shaders.h
@@ -87,22 +87,21 @@ static const char NETWORK_VIDEO_DEQUANT_SHADER_0[] =
   "  }\n"
   "}\n"
   "void main() {\n"
-  "  uint localIndex = gl_LocalInvocationIndex;\n"
-  "  int blockIndex = blockOffset + int(gl_WorkGroupID.y) * blockStride +\n"
+  "  uint localIndex   = gl_LocalInvocationIndex;\n"
+  "  int  blockIndex   = blockOffset + int(gl_WorkGroupID.y) * blockStride +\n"
   "    int(gl_WorkGroupID.x);\n"
-  "  uint sourceWord = offsets[blockIndex];\n"
-  "  uint subblock = bitfieldExtract(localIndex,0,3);\n"
-  "  uint blockX = bitfieldExtract(localIndex,3,2);\n"
-  "  uint blockY = bitfieldExtract(localIndex,5,2);\n"
-  "  uint group = blockY * 4u + blockX;\n"
-  "  ivec2 coord = ivec2(gl_WorkGroupID.xy) * 32 +\n"
+  "  uint sourceWord   = offsets[blockIndex];\n"
+  "  uint blockPresent = uint(sourceWord != 0xffffffffu);\n"
+  "  // Missing blocks must still reach every workgroup barrier.\n"
+  "  sourceWord *= blockPresent;\n"
+  "  uint  subblock = bitfieldExtract(localIndex,0,3);\n"
+  "  uint  blockX   = bitfieldExtract(localIndex,3,2);\n"
+  "  uint  blockY   = bitfieldExtract(localIndex,5,2);\n"
+  "  uint  group    = blockY * 4u + blockX;\n"
+  "  ivec2 coord    = ivec2(gl_WorkGroupID.xy) * 32 +\n"
   "    8 * ivec2(blockX,blockY) + unswizzle8x8(subblock << 3u);\n"
-  "  if (sourceWord == 0xffffffffu) {\n"
-  "    storeValues(coord,mat2x4(vec4(0.0),vec4(0.0)));\n"
-  "    return;\n"
-  "  }\n"
   "  uint sourceByte = sourceWord * 4u;\n"
-  "  uint ballot = payload[sourceWord] & 65535u;\n"
+  "  uint ballot     = (payload[sourceWord] & 65535u) * blockPresent;\n"
   "  if (localIndex == 0u) {\n"
   "    uint cursor = sourceByte + 8u + 3u * uint(bitCount(ballot));\n"
   "    for (uint index=0u; index<16u; ++index) {\n"
@@ -118,7 +117,7 @@ static const char NETWORK_VIDEO_DEQUANT_SHADER_0[] =
   "        cursor += uint(bitCount(low) + bitCount(high)) + 8u * qbits;\n"
   "      }\n"
   "    }\n"
-  "    signOffset = cursor * 8u;\n"
+  "    signOffset = cursor * 8u * blockPresent;\n"
   "  }\n"
   "  barrier();\n";