diff --git a/esphttpdconfig.mk b/esphttpdconfig.mk
index d8b6237..aa46aeb 100644
--- a/esphttpdconfig.mk
+++ b/esphttpdconfig.mk
@@ -39,15 +39,15 @@ OUTPUT_TYPE = combined
 ESP_SPI_FLASH_SIZE_K = 1024
 
 GLOBAL_CFLAGS = \
-    -DDEBUG_ROUTER=0 \
-    -DDEBUG_CAPTDNS=0 \
-    -DDEBUG_HTTP=0 \
-    -DDEBUG_ESPFS=0 \
-    -DDEBUG_PERSIST=0 \
-    -DDEBUG_UTFCACHE=0 \
+    -DDEBUG_ROUTER=1 \
+    -DDEBUG_CAPTDNS=1 \
+    -DDEBUG_HTTP=1 \
+    -DDEBUG_ESPFS=1 \
+    -DDEBUG_PERSIST=1 \
+    -DDEBUG_UTFCACHE=1 \
     -DDEBUG_CGI=0 \
     -DDEBUG_WIFI=0 \
-    -DDEBUG_WS=0 \
+    -DDEBUG_WS=1 \
     -DDEBUG_ANSI=1 \
     -DDEBUG_ANSI_NOIMPL=1 \
     -DDEBUG_INPUT=0 \
@@ -56,6 +56,6 @@ GLOBAL_CFLAGS = \
     -DHTTPD_MAX_BACKLOG_SIZE=8192 \
     -DHTTPD_MAX_HEAD_LEN=1024 \
     -DHTTPD_MAX_POST_LEN=512 \
-    -DDEBUG_LOGBUF_SIZE=1024 \
+    -DDEBUG_LOGBUF_SIZE=2048 \
     -mforce-l32 \
     -DUSE_OPTIMIZE_PRINTF=1
diff --git a/user/cgi_sockets.c b/user/cgi_sockets.c
index f3adcb8..9c7fac9 100644
--- a/user/cgi_sockets.c
+++ b/user/cgi_sockets.c
@@ -35,6 +35,8 @@ volatile int active_clients = 0;
 // this might glitch, very rarely.
 // it's recommended to put some delay between setting labels and updating the screen.
 
+static void resetHeartbeatTimer(void);
+
 /**
  * Cooldown delay is over
  * @param arg
@@ -66,6 +68,8 @@ notifyContentTimCb(void *arg)
 	}
 	notify_available = false;
 
+	resetHeartbeatTimer();
+
 	for (int i = 0; i < 20; i++) {
 		httpd_cgi_state cont = screenSerializeToBuffer(sock_buff, SOCK_BUF_LEN, &data);
 		int flg = 0;
@@ -108,6 +112,7 @@ notifyLabelsTimCb(void *arg)
 
 	screenSerializeLabelsToBuffer(sock_buff, SOCK_BUF_LEN);
 	cgiWebsockBroadcast(URL_WS_UPDATE, sock_buff, (int) strlen(sock_buff), 0);
+	resetHeartbeatTimer();
 
 	notify_cooldown = true;
 	notify_available = true;
@@ -123,6 +128,7 @@ send_beep(void)
 
 	// here's some potential for a race error with the other broadcast functions :C
 	cgiWebsockBroadcast(URL_WS_UPDATE, "B", 1, 0);
+	resetHeartbeatTimer();
 }
 
 
@@ -135,6 +141,7 @@ notify_growl(char *msg)
 	// TODO via timer...
 	// here's some potential for a race error with the other broadcast functions :C
 	cgiWebsockBroadcast(URL_WS_UPDATE, msg, (int) strlen(msg), 0);
+	resetHeartbeatTimer();
 }
 
 
@@ -170,7 +177,7 @@ void ICACHE_FLASH_ATTR screen_notifyChange(ScreenNotifyChangeTopic topic)
  * @param button - which button, 1-based. 0=none
  * @param mods - modifier keys bitmap: meta|alt|shift|ctrl
  */
-void ICACHE_FLASH_ATTR sendMouseAction(char evt, int y, int x, int button, u8 mods)
+static void ICACHE_FLASH_ATTR sendMouseAction(char evt, int y, int x, int button, u8 mods)
 {
 	// one-based
 	x++;
@@ -239,7 +246,7 @@ void ICACHE_FLASH_ATTR sendMouseAction(char evt, int y, int x, int button, u8 mo
 }
 
 /** Socket received a message */
-void ICACHE_FLASH_ATTR updateSockRx(Websock *ws, char *data, int len, int flags)
+static void ICACHE_FLASH_ATTR updateSockRx(Websock *ws, char *data, int len, int flags)
 {
 	// Add terminator if missing (seems to randomly happen)
 	data[len] = 0;
@@ -304,7 +311,7 @@ void ICACHE_FLASH_ATTR updateSockRx(Websock *ws, char *data, int len, int flags)
 }
 
 /** Send a heartbeat msg */
-void ICACHE_FLASH_ATTR heartbeatTimCb(void *unused)
+static void ICACHE_FLASH_ATTR heartbeatTimCb(void *unused)
 {
 	if (notify_available && active_clients > 0) {
 		// Heartbeat packet - indicate we're still connected
@@ -313,7 +320,13 @@ void ICACHE_FLASH_ATTR heartbeatTimCb(void *unused)
 	}
 }
 
-void ICACHE_FLASH_ATTR closeSockCb(Websock *ws)
+static void ICACHE_FLASH_ATTR resetHeartbeatTimer(void)
+{
+	TIMER_START(&heartbeatTim, heartbeatTimCb, HB_TIME, 1);
+}
+
+
+static void ICACHE_FLASH_ATTR closeSockCb(Websock *ws)
 {
 	active_clients--;
 	if (active_clients <= 0) {
@@ -340,7 +353,7 @@ void ICACHE_FLASH_ATTR updateSockConnect(Websock *ws)
 			UART_SendAsync("\x1b[I", 3);
 		}
 
-		TIMER_START(&heartbeatTim, heartbeatTimCb, HB_TIME, 1);
+		resetHeartbeatTimer();
 	}
 
 	active_clients++;
@@ -348,14 +361,14 @@ void ICACHE_FLASH_ATTR updateSockConnect(Websock *ws)
 
 ETSTimer xonTim;
 
-void ICACHE_FLASH_ATTR notify_empty_txbuf_cb(void *unused)
+static void ICACHE_FLASH_ATTR notify_empty_txbuf_cb(void *unused)
 {
 	UART_WriteChar(UART1, '+', 100);
 	cgiWebsockBroadcast(URL_WS_UPDATE, "+", 1, 0);
+	resetHeartbeatTimer();
 	browser_wants_xon = false;
 }
 
-
 void notify_empty_txbuf(void)
 {
 	if (browser_wants_xon) {
diff --git a/user/screen.c b/user/screen.c
index b753d59..057897b 100644
--- a/user/screen.c
+++ b/user/screen.c
@@ -545,6 +545,10 @@ screen_tab_reverse(int count)
 
 /**
  * Clear range, inclusive
+ *
+ * @param from - starting absolute position
+ * @param to - ending absolute position
+ * @param clear_utf - release any encountered utf8
  */
 static void ICACHE_FLASH_ATTR
 clear_range_do(unsigned int from, unsigned int to, bool clear_utf)
@@ -566,7 +570,10 @@ clear_range_do(unsigned int from, unsigned int to, bool clear_utf)
 }
 
 /**
- * Clear range, inclusive
+ * Clear range, inclusive, freeing any encountered UTF8 from the cache
+ *
+ * @param from - starting absolute position
+ * @param to - ending absolute position
  */
 static inline void ICACHE_FLASH_ATTR
 clear_range_utf(unsigned int from, unsigned int to)
@@ -576,6 +583,9 @@ clear_range_utf(unsigned int from, unsigned int to)
 
 /**
  * Clear range, inclusive. Do not release utf characters
+ *
+ * @param from - starting absolute position
+ * @param to - ending absolute position
  */
 static inline void ICACHE_FLASH_ATTR
 clear_range_noutf(unsigned int from, unsigned int to)
@@ -583,44 +593,105 @@ clear_range_noutf(unsigned int from, unsigned int to)
 	clear_range_do(from, to, false);
 }
 
+/**
+ * Free a utf8 reference character in a cell
+ *
+ * @param row
+ * @param col
+ */
 static inline void ICACHE_FLASH_ATTR
-utf_free_cell(int row, int i)
+utf_free_cell(int row, int col)
 {
-	UnicodeCacheRef symbol = screen[row * W + i].symbol;
+	UnicodeCacheRef symbol = screen[row * W + col].symbol;
 	if (IS_UNICODE_CACHE_REF(symbol))
 		unicode_cache_remove(symbol);
 }
 
+/**
+ * Back-up utf8 reference in a cell (i.e. increment the counter,
+ * so 1 subsequent free has no effect)
+ *
+ * @param row
+ * @param col
+ */
+static inline void ICACHE_FLASH_ATTR
+utf_backup_cell(int row, int col)
+{
+	UnicodeCacheRef symbol = screen[row * W + col].symbol;
+	if (IS_UNICODE_CACHE_REF(symbol))
+		unicode_cache_inc(symbol);
+}
+
+/**
+ * Free all utf8 on a row
+ *
+ * @param row
+ */
 static inline void ICACHE_FLASH_ATTR
-utf_free_row(int r)
+utf_free_row(int row)
 {
-	for (int i = 0; i < W; i++) {
-		utf_free_cell(r, i);
+	for (int col = 0; col < W; col++) {
+		utf_free_cell(row, col);
 	}
 }
 
+/**
+ * Back-up all utf8 refs on a row
+ *
+ * @param row
+ */
+static inline void ICACHE_FLASH_ATTR
+utf_backup_row(int row)
+{
+	for (int col = 0; col < W; col++) {
+		utf_backup_cell(row, col);
+	}
+}
+
+/**
+ * Duplicate a row
+ *
+ * @param dest - destination row number (0-based)
+ * @param src  - source row number (0-based)
+ */
 static inline void ICACHE_FLASH_ATTR
 copy_row(int dest, int src)
 {
 	memcpy(screen + dest * W, screen + src * W, sizeof(Cell) * W);
 }
 
+/**
+ * Duplicate a cell within a row
+ * @param row - row to work on
+ * @param dest_col - destination column
+ * @param src_col - source column
+ */
 static inline void ICACHE_FLASH_ATTR
 copy_cell(int row, int dest_col, int src_col)
 {
 	memcpy(screen+row*W+dest_col, screen+row*W+src_col, sizeof(Cell));
 }
 
+/**
+ * Clear a row, do nothing with the utf8 cache
+ *
+ * @param row
+ */
 static inline void ICACHE_FLASH_ATTR
-clear_row_noutf(int r)
+clear_row_noutf(int row)
 {
-	clear_range_noutf(r * W, (r + 1) * W - 1);
+	clear_range_noutf(row * W, (row + 1) * W - 1);
 }
 
+/**
+ * Clear a row, freeing any utf8 refs
+ *
+ * @param row
+ */
 static inline void ICACHE_FLASH_ATTR
-clear_row_utf(int r)
+clear_row_utf(int row)
 {
-	clear_range_utf(r * W, (r + 1) * W - 1);
+	clear_range_utf(row * W, (row + 1) * W - 1);
 }
 
 /**
@@ -633,7 +704,8 @@ screen_clear(ClearMode mode)
 	NOTIFY_LOCK();
 	switch (mode) {
 		case CLEAR_ALL:
-			clear_range_utf(0, W * H - 1);
+			clear_range_noutf(0, W * H - 1);
+			unicode_cache_clear();
 			break;
 
 		case CLEAR_FROM_CURSOR:
@@ -691,20 +763,20 @@ screen_insert_lines(unsigned int lines)
 	// shift the following lines
 	int targetStart = cursor.y + lines;
 	if (targetStart > BTM) {
-		targetStart = BTM - 1;
+		clear_range_utf(cursor.y*W, (BTM+1)*W-1);
 	} else {
 		// do the moving
 		for (int i = BTM; i >= targetStart; i--) {
 			utf_free_row(i); // release old characters
 			copy_row(i, i - lines);
 		}
-	}
 
-	// clear the first line
-	clear_row_noutf(CLEAR_ALL);
-	// copy it to the rest of the cleared region
-	for (int i = cursor.y+1; i < targetStart; i++) {
-		copy_row(i, cursor.y);
+		// clear the first line
+		clear_row_noutf(cursor.y);
+		// copy it to the rest of the cleared region
+		for (int i = cursor.y+1; i < targetStart; i++) {
+			copy_row(i, cursor.y);
+		}
 	}
 	NOTIFY_DONE();
 }
@@ -716,18 +788,18 @@ screen_delete_lines(unsigned int lines)
 	NOTIFY_LOCK();
 
 	// shift lines up
-	int targetEnd = BTM - lines - 1;
-	if (targetEnd <= cursor.y) {
+	int movedBlockEnd = BTM - lines ;
+	if (movedBlockEnd <= cursor.y) {
 		// clear the entire rest of the screen
-		targetEnd = cursor.y;
-		clear_range_utf(targetEnd * W, W * BTM);
+		movedBlockEnd = cursor.y;
+		clear_range_utf(movedBlockEnd*W, W * BTM);
 	} else {
 		// move some lines up, clear the rest
-		for (int i = cursor.y; i <= targetEnd; i++) {
+		for (int i = cursor.y; i <= movedBlockEnd; i++) {
 			utf_free_row(i);
 			copy_row(i, i+lines);
 		}
-		clear_range_noutf(targetEnd*W, W*BTM);
+		clear_range_noutf((movedBlockEnd+1)*W, (BTM+1)*W-1);
 	}
 
 	NOTIFY_DONE();
@@ -743,8 +815,7 @@ screen_insert_characters(unsigned int count)
 	int targetStart = cursor.x + count;
 	if (targetStart >= W) {
 		// all rest of line was cleared
-		targetStart = W-1;
-		clear_range_utf(cursor.y * W + cursor.x, cursor.y * W + targetStart - 1);
+		clear_range_utf(cursor.y * W + cursor.x, (cursor.y + 1) * W - 1);
 	} else {
 		// do the moving
 		for (int i = W-1; i >= targetStart; i--) {
diff --git a/user/utf8.c b/user/utf8.c
index bc67de0..3d4c693 100644
--- a/user/utf8.c
+++ b/user/utf8.c
@@ -20,7 +20,8 @@ static UnicodeCacheSlot cache[UNICODE_CACHE_SIZE];
  * @return
  */
 void ICACHE_FLASH_ATTR
-unicode_cache_clear(void) {
+unicode_cache_clear(void)
+{
 	utfc_dbg("utf8 cache clear!");
 	for (int slot = 0; slot < UNICODE_CACHE_SIZE; slot++) {
 		cache[slot].count=0;
@@ -35,7 +36,8 @@ unicode_cache_clear(void) {
  * @return the obtained look-up reference
  */
 UnicodeCacheRef ICACHE_FLASH_ATTR
-unicode_cache_add(const u8 *bytes) {
+unicode_cache_add(const u8 *bytes)
+{
 	if (bytes[0] < 32) {
 		utfc_warn("utf8 cache bad char '%c'", bytes[0]);
 		return '?';
@@ -69,6 +71,27 @@ unicode_cache_add(const u8 *bytes) {
 	return ID_TO_REF(slot);
 }
 
+/**
+ * Increment a reference
+ *
+ * @param ref - reference
+ * @return success
+ */
+bool ICACHE_FLASH_ATTR
+unicode_cache_inc(UnicodeCacheRef ref)
+{
+	if (!IS_UNICODE_CACHE_REF(ref)) return true; // ASCII
+
+	int slot = REF_TO_ID(ref);
+	if (cache[slot].count == 0) {
+		utfc_warn("utf8 cache inc-after-free ref @ %d", ref);
+		return false;
+	}
+	cache[slot].count++;
+	utfc_dbg("utf8 cache inc '%.4s' @ %d, %d uses", cache[slot].bytes, slot, cache[slot].count);
+	return true;
+}
+
 /**
  * Look up a code point in the cache by reference. Do not change the use counter.
  *
@@ -77,7 +100,8 @@ unicode_cache_add(const u8 *bytes) {
  * @return true if the look-up succeeded
  */
 bool ICACHE_FLASH_ATTR
-unicode_cache_retrieve(UnicodeCacheRef ref, u8 *target) {
+unicode_cache_retrieve(UnicodeCacheRef ref, u8 *target)
+{
 	if (!IS_UNICODE_CACHE_REF(ref)) {
 		// ASCII, bypass
 		target[0] = ref;
@@ -107,7 +131,8 @@ unicode_cache_retrieve(UnicodeCacheRef ref, u8 *target) {
  * @return true if the code point was found in the cache
  */
 bool ICACHE_FLASH_ATTR
-unicode_cache_remove(UnicodeCacheRef ref) {
+unicode_cache_remove(UnicodeCacheRef ref)
+{
 	if (!IS_UNICODE_CACHE_REF(ref)) return true; // ASCII, bypass
 
 	u8 slot = REF_TO_ID(ref);
diff --git a/user/utf8.h b/user/utf8.h
index 81f9372..c24bf07 100644
--- a/user/utf8.h
+++ b/user/utf8.h
@@ -28,6 +28,14 @@ void unicode_cache_clear(void);
  */
 UnicodeCacheRef unicode_cache_add(const u8 *bytes);
 
+/**
+ * Increment a reference
+ *
+ * @param ref - reference
+ * @return success
+ */
+bool unicode_cache_inc(UnicodeCacheRef ref);
+
 /**
  * Look up a code point in the cache by reference. Do not change the use counter.
  *