diff --git a/client/X11/xf_cliprdr.c b/client/X11/xf_cliprdr.c
index bb586a00e..7961b1cd1 100644
--- a/client/X11/xf_cliprdr.c
+++ b/client/X11/xf_cliprdr.c
@@ -172,6 +172,9 @@ struct xf_clipboard
 	BOOL streams_supported;
 	BOOL file_formats_registered;
 	UINT32 file_capability_flags;
+	/* last sent data */
+	CLIPRDR_FORMAT* lastSentFormats;
+	UINT32 lastSentNumFormats;
 #ifdef WITH_FUSE
 	/* FUSE related**/
 	HANDLE fuse_thread;
@@ -343,9 +346,17 @@ static UINT xf_cliprdr_send_data_request(xfClipboard* clipboard, UINT32 formatId
  *
  * @return 0 on success, otherwise a Win32 error code
  */
-static UINT xf_cliprdr_send_data_response(xfClipboard* clipboard, BYTE* data, int size)
+static UINT xf_cliprdr_send_data_response(xfClipboard* clipboard, const BYTE* data, size_t size)
 {
 	CLIPRDR_FORMAT_DATA_RESPONSE response = { 0 };
+
+	/* No request currently pending, do not send a response. */
+	if (clipboard->requestedFormatId < 0)
+		return CHANNEL_RC_OK;
+
+	/* Request handled, reset to invalid */
+	clipboard->requestedFormatId = -1;
+
 	response.msgFlags = (data) ? CB_RESPONSE_OK : CB_RESPONSE_FAIL;
 	response.dataLen = size;
 	response.requestedFormatData = data;
@@ -599,17 +610,92 @@ static void xf_cliprdr_provide_server_format_list(xfClipboard* clipboard)
 	Stream_Free(formats, TRUE);
 }
 
+static BOOL xf_clipboard_format_equal(const CLIPRDR_FORMAT* a, const CLIPRDR_FORMAT* b)
+{
+	if (a->formatId != b->formatId)
+		return FALSE;
+	if (!a->formatName && !b->formatName)
+		return TRUE;
+
+	return strcmp(a->formatName, b->formatName) == 0;
+}
+static BOOL xf_clipboard_changed(xfClipboard* clipboard, const CLIPRDR_FORMAT* formats,
+                                 UINT32 numFormats)
+{
+	UINT32 x, y;
+	if (clipboard->lastSentNumFormats != numFormats)
+		return TRUE;
+
+	for (x = 0; x < numFormats; x++)
+	{
+		const CLIPRDR_FORMAT* cur = &clipboard->lastSentFormats[x];
+		BOOL contained = FALSE;
+		for (y = 0; y < numFormats; y++)
+		{
+			if (xf_clipboard_format_equal(cur, &formats[y]))
+			{
+				contained = TRUE;
+				break;
+			}
+		}
+		if (!contained)
+			return TRUE;
+	}
+
+	return FALSE;
+}
+
+static void xf_clipboard_formats_free(xfClipboard* clipboard)
+{
+	xf_cliprdr_free_formats(clipboard->lastSentFormats, clipboard->lastSentNumFormats);
+	clipboard->lastSentFormats = NULL;
+	clipboard->lastSentNumFormats = 0;
+}
+static BOOL xf_clipboard_copy_formats(xfClipboard* clipboard, const CLIPRDR_FORMAT* formats,
+                                      UINT32 numFormats)
+{
+	UINT32 x;
+
+	xf_clipboard_formats_free(clipboard);
+	clipboard->lastSentFormats = calloc(numFormats, sizeof(CLIPRDR_FORMAT));
+	if (!clipboard->lastSentFormats)
+		return FALSE;
+	clipboard->lastSentNumFormats = numFormats;
+	for (x = 0; x < numFormats; x++)
+	{
+		CLIPRDR_FORMAT* lcur = &clipboard->lastSentFormats[x];
+		const CLIPRDR_FORMAT* cur = &formats[x];
+		*lcur = *cur;
+		if (cur->formatName)
+			lcur->formatName = _strdup(cur->formatName);
+	}
+	return FALSE;
+}
+
+static UINT xf_cliprdr_send_format_list(xfClipboard* clipboard, const CLIPRDR_FORMAT* formats,
+                                        UINT32 numFormats)
+{
+	CLIPRDR_FORMAT_LIST formatList = { 0 };
+	formatList.msgFlags = CB_RESPONSE_OK;
+	formatList.numFormats = numFormats;
+	formatList.formats = (CLIPRDR_FORMAT*)formats;
+	formatList.msgType = CB_FORMAT_LIST;
+
+	if (!xf_clipboard_changed(clipboard, formats, numFormats))
+		return CHANNEL_RC_OK;
+
+	xf_clipboard_copy_formats(clipboard, formats, numFormats);
+	/* Ensure all pending requests are answered. */
+	xf_cliprdr_send_data_response(clipboard, NULL, 0);
+	return clipboard->context->ClientFormatList(clipboard->context, &formatList);
+}
+
 static void xf_cliprdr_get_requested_targets(xfClipboard* clipboard)
 {
 	UINT32 numFormats = 0;
 	CLIPRDR_FORMAT* formats = NULL;
-	CLIPRDR_FORMAT_LIST formatList = { 0 };
 	formats = xf_cliprdr_get_client_formats(clipboard, &numFormats);
-	formatList.msgFlags = CB_RESPONSE_OK;
-	formatList.numFormats = numFormats;
-	formatList.formats = formats;
-	formatList.msgType = CB_FORMAT_LIST;
-	clipboard->context->ClientFormatList(clipboard->context, &formatList);
+	xf_cliprdr_send_format_list(clipboard, formats, numFormats);
 	xf_cliprdr_free_formats(formats, numFormats);
 }
 
@@ -707,7 +793,7 @@ static void xf_cliprdr_process_requested_data(xfClipboard* clipboard, BOOL hasDa
 		free(file_array);
 	}
 
-	xf_cliprdr_send_data_response(clipboard, pDstData, (int)DstSize);
+	xf_cliprdr_send_data_response(clipboard, pDstData, DstSize);
 	free(pDstData);
 }
 
@@ -722,6 +808,7 @@ static BOOL xf_cliprdr_get_requested_data(xfClipboard* clipboard, Atom target)
 	unsigned long bytes_left;
 	xfCliprdrFormat* format;
 	xfContext* xfc = clipboard->xfc;
+
 	format = xf_cliprdr_get_client_format_by_id(clipboard, clipboard->requestedFormatId);
 
 	if (!format || (format->atom != target))
@@ -778,14 +865,16 @@ static BOOL xf_cliprdr_get_requested_data(xfClipboard* clipboard, Atom target)
 				new_data =
 				    (BYTE*)realloc(clipboard->incr_data, clipboard->incr_data_length + bytes_left);
 
-				if (!new_data)
-					return FALSE;
+				if (new_data)
+				{
 
-				clipboard->incr_data = new_data;
-				CopyMemory(clipboard->incr_data + clipboard->incr_data_length, data, bytes_left);
-				clipboard->incr_data_length += bytes_left;
-				XFree(data);
-				data = NULL;
+					clipboard->incr_data = new_data;
+					CopyMemory(clipboard->incr_data + clipboard->incr_data_length, data,
+					           bytes_left);
+					clipboard->incr_data_length += bytes_left;
+					XFree(data);
+					data = NULL;
+				}
 			}
 
 			has_data = TRUE;
@@ -796,7 +885,7 @@ static BOOL xf_cliprdr_get_requested_data(xfClipboard* clipboard, Atom target)
 	}
 
 	XDeleteProperty(xfc->display, xfc->drawable, clipboard->property_atom);
-	xf_cliprdr_process_requested_data(clipboard, has_data, data, (int)bytes_left);
+	xf_cliprdr_process_requested_data(clipboard, has_data, data, bytes_left);
 
 	if (data)
 		XFree(data);
@@ -1204,7 +1293,6 @@ static UINT xf_cliprdr_send_client_format_list(xfClipboard* clipboard)
 {
 	UINT32 i, numFormats;
 	CLIPRDR_FORMAT* formats = NULL;
-	CLIPRDR_FORMAT_LIST formatList = { 0 };
 	xfContext* xfc = clipboard->xfc;
 	UINT ret;
 	numFormats = clipboard->numClientFormats;
@@ -1224,11 +1312,7 @@ static UINT xf_cliprdr_send_client_format_list(xfClipboard* clipboard)
 		formats[i].formatName = clipboard->clientFormats[i].formatName;
 	}
 
-	formatList.msgFlags = CB_RESPONSE_OK;
-	formatList.numFormats = numFormats;
-	formatList.formats = formats;
-	formatList.msgType = CB_FORMAT_LIST;
-	ret = clipboard->context->ClientFormatList(clipboard->context, &formatList);
+	ret = xf_cliprdr_send_format_list(clipboard, formats, numFormats);
 	free(formats);
 
 	if (clipboard->owner && clipboard->owner != xfc->drawable)
@@ -1501,6 +1585,7 @@ static UINT xf_cliprdr_server_format_list(CliprdrClientContext* context,
 	xfClipboard* clipboard = (xfClipboard*)context->custom;
 	xfContext* xfc = clipboard->xfc;
 	UINT ret;
+	xf_clipboard_formats_free(clipboard);
 	xf_cliprdr_clear_cached_data(clipboard);
 	clipboard->data_format_id = -1;
 	clipboard->data_format_name = NULL;
@@ -1613,10 +1698,10 @@ xf_cliprdr_server_format_data_request(CliprdrClientContext* context,
 	else
 		format = xf_cliprdr_get_client_format_by_id(clipboard, formatId);
 
+	clipboard->requestedFormatId = rawTransfer ? CF_RAW : formatId;
 	if (!format)
 		return xf_cliprdr_send_data_response(clipboard, NULL, 0);
 
-	clipboard->requestedFormatId = rawTransfer ? CF_RAW : formatId;
 	XConvertSelection(xfc->display, clipboard->clipboard_atom, format->atom,
 	                  clipboard->property_atom, xfc->drawable, CurrentTime);
 	XFlush(xfc->display);
@@ -2914,6 +2999,7 @@ void xf_clipboard_free(xfClipboard* clipboard)
 #endif
 
 	ClipboardDestroy(clipboard->system);
+	xf_clipboard_formats_free(clipboard);
 	free(clipboard->data);
 	free(clipboard->data_raw);
 	free(clipboard->respond);