diff --git a/buffer/buffer.go b/buffer/buffer.go
index 8fa1424..bbf580f 100644
--- a/buffer/buffer.go
+++ b/buffer/buffer.go
@@ -19,6 +19,7 @@ type Buffer struct {
 	bottomMargin          uint // see DECSTBM docs - this is for scrollable regions
 	replaceMode           bool // overwrite character at cursor or insert new
 	autoWrap              bool
+	dirty                 bool
 }
 
 // NewBuffer creates a new terminal buffer
@@ -35,6 +36,14 @@ func NewBuffer(viewCols uint16, viewLines uint16, attr CellAttributes) *Buffer {
 	return b
 }
 
+func (buffer *Buffer) IsDirty() bool {
+	if !buffer.dirty {
+		return false
+	}
+	buffer.dirty = false
+	return true
+}
+
 func (buffer *Buffer) SetAutoWrap(enabled bool) {
 	buffer.autoWrap = enabled
 }
@@ -132,23 +141,8 @@ func (buffer *Buffer) GetCell(viewCol uint16, viewRow uint16) *Cell {
 	return &line.cells[viewCol]
 }
 
-func (buffer *Buffer) AttachDisplayChangeHandler(handler chan bool) {
-	if buffer.displayChangeHandlers == nil {
-		buffer.displayChangeHandlers = []chan bool{}
-	}
-
-	buffer.displayChangeHandlers = append(buffer.displayChangeHandlers, handler)
-}
-
 func (buffer *Buffer) emitDisplayChange() {
-	for _, channel := range buffer.displayChangeHandlers {
-		go func(c chan bool) {
-			select {
-			case c <- true:
-			default:
-			}
-		}(channel)
-	}
+	buffer.dirty = true
 }
 
 // Column returns cursor column
@@ -219,7 +213,7 @@ func (buffer *Buffer) insertLine() {
 		copy(out[0:], before)
 
 		pos := buffer.RawLine()
-		for i := topIndex; i <= bottomIndex; i++ {
+		for i := topIndex; i < bottomIndex; i++ {
 			if i < pos {
 				out[i] = buffer.lines[i]
 			} else {
@@ -227,7 +221,7 @@ func (buffer *Buffer) insertLine() {
 			}
 		}
 
-		copy(out[bottomIndex:], after)
+		copy(out[bottomIndex+1:], after)
 
 		out[pos] = newLine()
 		buffer.lines = out
@@ -260,17 +254,18 @@ func (buffer *Buffer) Index() {
 
 		if uint(buffer.cursorY) < buffer.bottomMargin {
 			buffer.cursorY++
+		} else {
+
+			topIndex := buffer.convertViewLineToRawLine(uint16(buffer.topMargin))
+			bottomIndex := buffer.convertViewLineToRawLine(uint16(buffer.bottomMargin))
+
+			for i := topIndex; i < bottomIndex; i++ {
+				buffer.lines[i] = buffer.lines[i+1]
+			}
+
+			buffer.lines[bottomIndex] = newLine()
 		}
 
-		topIndex := buffer.convertViewLineToRawLine(uint16(buffer.topMargin))
-		bottomIndex := buffer.convertViewLineToRawLine(uint16(buffer.bottomMargin))
-
-		for i := topIndex; i < bottomIndex; i++ {
-			buffer.lines[i] = buffer.lines[i+1]
-		}
-
-		buffer.lines[buffer.RawLine()] = newLine()
-
 		return
 	}
 
@@ -289,17 +284,17 @@ func (buffer *Buffer) ReverseIndex() {
 
 		if uint(buffer.cursorY) > buffer.topMargin {
 			buffer.cursorY--
+		} else {
+
+			topIndex := buffer.convertViewLineToRawLine(uint16(buffer.topMargin))
+			bottomIndex := buffer.convertViewLineToRawLine(uint16(buffer.bottomMargin))
+
+			for i := bottomIndex; i > topIndex; i-- {
+				buffer.lines[i] = buffer.lines[i-1]
+			}
+
+			buffer.lines[topIndex] = newLine()
 		}
-
-		topIndex := buffer.convertViewLineToRawLine(uint16(buffer.topMargin))
-		bottomIndex := buffer.convertViewLineToRawLine(uint16(buffer.bottomMargin))
-
-		for i := bottomIndex; i > topIndex; i-- {
-			buffer.lines[i] = buffer.lines[i-1]
-		}
-
-		buffer.lines[buffer.RawLine()] = newLine()
-
 		return
 	}
 
@@ -520,10 +515,9 @@ func (buffer *Buffer) EraseLineFromCursor() {
 
 	if len(line.cells) > 0 {
 		cx := buffer.cursorX
-		if int(cx) >= len(line.cells) {
-			return // nothing to delete
+		if int(cx) < len(line.cells) {
+			line.cells = line.cells[:buffer.cursorX]
 		}
-		line.cells = line.cells[:buffer.cursorX]
 	}
 
 	max := int(buffer.ViewWidth()) - len(line.cells)
@@ -545,6 +539,15 @@ func (buffer *Buffer) EraseDisplay() {
 	}
 }
 
+func (buffer *Buffer) DeleteChars(n int) {
+	defer buffer.emitDisplayChange()
+
+	line := buffer.getCurrentLine()
+	before := line.cells[:buffer.cursorX]
+	after := line.cells[int(buffer.cursorX)+n:]
+	line.cells = append(before, after...)
+}
+
 func (buffer *Buffer) EraseCharacters(n int) {
 	defer buffer.emitDisplayChange()
 
diff --git a/buffer/buffer_test.go b/buffer/buffer_test.go
index 9b864e5..330b06e 100644
--- a/buffer/buffer_test.go
+++ b/buffer/buffer_test.go
@@ -3,7 +3,6 @@ package buffer
 import (
 	"strings"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/require"
 
@@ -298,29 +297,6 @@ func TestCursorAttr(t *testing.T) {
 	assert.Equal(t, &b.cursorAttr, b.CursorAttr())
 }
 
-func TestAttachingHandlers(t *testing.T) {
-	b := NewBuffer(80, 2, CellAttributes{})
-	displayHandler := make(chan bool, 1)
-	b.AttachDisplayChangeHandler(displayHandler)
-	require.Equal(t, 1, len(b.displayChangeHandlers))
-	assert.Equal(t, b.displayChangeHandlers[0], displayHandler)
-}
-
-func TestEmitDisplayHandlers(t *testing.T) {
-	b := NewBuffer(80, 2, CellAttributes{})
-	displayHandler := make(chan bool, 1)
-	b.AttachDisplayChangeHandler(displayHandler)
-	b.emitDisplayChange()
-	time.Sleep(time.Millisecond * 50)
-	ok := false
-	select {
-	case <-displayHandler:
-		ok = true
-	default:
-	}
-	assert.True(t, ok)
-}
-
 func TestCursorPositionQuerying(t *testing.T) {
 	b := NewBuffer(80, 20, CellAttributes{})
 	b.cursorX = 17
diff --git a/gui/input.go b/gui/input.go
index b0ed1cd..febf3db 100644
--- a/gui/input.go
+++ b/gui/input.go
@@ -158,8 +158,6 @@ func (gui *GUI) key(w *glfw.Window, key glfw.Key, scancode int, action glfw.Acti
 				if gui.terminal.IsApplicationCursorKeysModeEnabled() {
 					gui.terminal.Write([]byte{
 						0x1b,
-						'O',
-						0x1b,
 					})
 				} else {
 					gui.terminal.Write([]byte{
diff --git a/terminal/csi.go b/terminal/csi.go
index b122c5f..d1e8b1f 100644
--- a/terminal/csi.go
+++ b/terminal/csi.go
@@ -28,7 +28,7 @@ var csiSequences = []csiMapping{
 	csiMapping{id: 'l', handler: csiResetModeHandler, expectedParams: &expectedParams{min: 1, max: 1}, description: "Reset Mode (RM)"},
 	csiMapping{id: 'm', handler: sgrSequenceHandler, description: "Character Attributes (SGR)"},
 	csiMapping{id: 'n', handler: csiDeviceStatusReportHandler, description: "Device Status Report (DSR)"},
-	csiMapping{id: 'r', handler: csiSetMarginsHandler, expectedParams: &expectedParams{min: 2, max: 2}, description: "Set Scrolling Region [top;bottom] (default = full size of window) (DECSTBM), VT100"},
+	csiMapping{id: 'r', handler: csiSetMarginsHandler, expectedParams: &expectedParams{min: 0, max: 2}, description: "Set Scrolling Region [top;bottom] (default = full size of window) (DECSTBM), VT100"},
 	csiMapping{id: 't', handler: csiWindowManipulation, description: "Window manipulation"},
 	csiMapping{id: 'A', handler: csiCursorUpHandler, description: "Cursor Up Ps Times (default = 1) (CUU)"},
 	csiMapping{id: 'B', handler: csiCursorDownHandler, description: "Cursor Down Ps Times (default = 1) (CUD)"},
@@ -77,8 +77,9 @@ CSI:
 			if sequence.expectedParams != nil && (uint8(len(params)) < sequence.expectedParams.min || uint8(len(params)) > sequence.expectedParams.max) {
 				continue
 			}
-			terminal.logger.Debugf("CSI 0x%02X (ESC[%s%s%s) %s", final, param, intermediate, string(final), sequence.description)
+			x, y := terminal.ActiveBuffer().CursorColumn(), terminal.ActiveBuffer().CursorLine()
 			err := sequence.handler(params, intermediate, terminal)
+			terminal.logger.Debugf("CSI 0x%02X (ESC[%s%s%s) %s - %d,%d -> %d,%d", final, param, intermediate, string(final), sequence.description, x, y, terminal.ActiveBuffer().CursorColumn(), terminal.ActiveBuffer().CursorLine())
 			return err
 		}
 	}
@@ -377,8 +378,7 @@ func csiDeleteHandler(params []string, intermediate string, terminal *Terminal)
 		}
 	}
 
-	terminal.ActiveBuffer().EraseCharacters(n)
-
+	terminal.ActiveBuffer().DeleteChars(n)
 	return nil
 }
 
diff --git a/terminal/output.go b/terminal/output.go
index 99b6064..1ff4d10 100644
--- a/terminal/output.go
+++ b/terminal/output.go
@@ -98,7 +98,7 @@ func (terminal *Terminal) processInput(ctx context.Context, pty chan rune) {
 		} else {
 			//terminal.logger.Debugf("Received character 0x%X: %q", b, string(b))
 			if b >= 0x20 {
-				terminal.logger.Debugf("%c", b)
+				//terminal.logger.Debugf("%c", b)
 				terminal.ActiveBuffer().Write(b)
 			} else {
 				terminal.logger.Error("Non-readable rune received: 0x%X", b)
diff --git a/terminal/terminal.go b/terminal/terminal.go
index 6a42990..b5c1fc6 100644
--- a/terminal/terminal.go
+++ b/terminal/terminal.go
@@ -100,7 +100,7 @@ func (terminal *Terminal) SetBracketedPasteMode(enabled bool) {
 func (terminal *Terminal) CheckDirty() bool {
 	d := terminal.isDirty
 	terminal.isDirty = false
-	return d
+	return d || terminal.ActiveBuffer().IsDirty()
 }
 
 func (terminal *Terminal) SetDirty() {
@@ -166,12 +166,6 @@ func (terminal *Terminal) GetCell(col uint16, row uint16) *buffer.Cell {
 	return terminal.ActiveBuffer().GetCell(col, row)
 }
 
-func (terminal *Terminal) AttachDisplayChangeHandler(handler chan bool) {
-	for i := range terminal.buffers {
-		terminal.buffers[i].AttachDisplayChangeHandler(handler)
-	}
-}
-
 func (terminal *Terminal) AttachTitleChangeHandler(handler chan bool) {
 	terminal.titleHandlers = append(terminal.titleHandlers, handler)
 }