diff --git a/client/src/core.c b/client/src/core.c
index 0cb4bde6..86ffed7f 100644
--- a/client/src/core.c
+++ b/client/src/core.c
@@ -190,6 +190,21 @@ bool core_warpPointer(int x, int y, bool exiting)
 
 void core_updatePositionInfo(void)
 {
+  if (g_state.kvmfrFeatures & KVMFR_FEATURE_WINDOWSIZE)
+  {
+    const KVMFRWindowSize msg = {
+      .msg.type = KVMFR_MESSAGE_WINDOWSIZE,
+      .w        = g_state.windowW,
+      .h        = g_state.windowH
+    };
+
+    uint32_t serial;
+    LGMP_STATUS status;
+    if ((status = lgmpClientSendData(g_state.pointerQueue,
+          &msg, sizeof(msg), &serial)) != LGMP_OK)
+      DEBUG_WARN("Message send failed: %s", lgmpStatusString(status));
+  }
+
   if (!g_state.haveSrcSize)
     goto done;
 
diff --git a/common/include/common/KVMFR.h b/common/include/common/KVMFR.h
index 8e18e5b7..16ef0343 100644
--- a/common/include/common/KVMFR.h
+++ b/common/include/common/KVMFR.h
@@ -56,14 +56,16 @@ typedef uint32_t KVMFRCursorFlags;
 
 enum
 {
-  KVMFR_FEATURE_SETCURSORPOS = 0x1
+  KVMFR_FEATURE_SETCURSORPOS = 0x1,
+  KVMFR_FEATURE_WINDOWSIZE   = 0x2
 };
 
 typedef uint32_t KVMFRFeatureFlags;
 
 enum
 {
-  KVMFR_MESSAGE_SETCURSORPOS
+  KVMFR_MESSAGE_SETCURSORPOS,
+  KVMFR_MESSAGE_WINDOWSIZE
 };
 
 typedef uint32_t KVMFRMessageType;
@@ -176,6 +178,13 @@ typedef struct KVMFRSetCursorPos
 }
 KVMFRSetCursorPos;
 
+typedef struct KVMFRWindowSize
+{
+  KVMFRMessage msg;
+  uint32_t w, h;
+}
+KVMFRWindowSize;
+
 #ifdef _MSC_VER
 #pragma warning(pop)
 #endif