diff --git a/buffer/buffer.go b/buffer/buffer.go
index 9065ecb..dcfcc07 100644
--- a/buffer/buffer.go
+++ b/buffer/buffer.go
@@ -27,6 +27,7 @@ type Buffer struct {
 	selectionComplete     bool // whether the selected text can update or whether it is final
 	selectionExpanded     bool // whether the selection to word expansion has already run on this point
 	selectionClickTime    time.Time
+	defaultCell           Cell
 }
 
 type Position struct {
@@ -37,11 +38,12 @@ type Position struct {
 // NewBuffer creates a new terminal buffer
 func NewBuffer(viewCols uint16, viewLines uint16, attr CellAttributes) *Buffer {
 	b := &Buffer{
-		cursorX:    0,
-		cursorY:    0,
-		lines:      []Line{},
-		cursorAttr: attr,
-		autoWrap:   true,
+		cursorX:     0,
+		cursorY:     0,
+		lines:       []Line{},
+		cursorAttr:  attr,
+		autoWrap:    true,
+		defaultCell: Cell{attr: attr},
 	}
 	b.SetVerticalMargins(0, uint(viewLines-1))
 	b.ResizeView(viewCols, viewLines)
@@ -511,8 +513,7 @@ func (buffer *Buffer) InsertBlankCharacters(count int) {
 	index := int(buffer.RawLine())
 	for i := 0; i < count; i++ {
 		cells := buffer.lines[index].cells
-		c := Cell{}
-		buffer.lines[index].cells = append(cells[:buffer.cursorX], append([]Cell{c}, cells[buffer.cursorX:]...)...)
+		buffer.lines[index].cells = append(cells[:buffer.cursorX], append([]Cell{buffer.defaultCell}, cells[buffer.cursorX:]...)...)
 	}
 }
 
@@ -624,7 +625,7 @@ func (buffer *Buffer) Write(runes ...rune) {
 			}
 
 			for int(buffer.CursorColumn()) >= len(line.cells) {
-				line.cells = append(line.cells, Cell{})
+				line.cells = append(line.cells, buffer.defaultCell)
 			}
 			line.cells[buffer.cursorX].attr = buffer.cursorAttr
 			line.cells[buffer.cursorX].setRune(r)
@@ -655,7 +656,7 @@ func (buffer *Buffer) Write(runes ...rune) {
 		} else {
 
 			for int(buffer.CursorColumn()) >= len(line.cells) {
-				line.cells = append(line.cells, Cell{})
+				line.cells = append(line.cells, buffer.defaultCell)
 			}
 
 			cell := &line.cells[buffer.CursorColumn()]
diff --git a/gui/gui.go b/gui/gui.go
index 328c497..a1a1a68 100644
--- a/gui/gui.go
+++ b/gui/gui.go
@@ -6,6 +6,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/go-gl/gl/all-core/gl"
@@ -33,6 +34,7 @@ type GUI struct {
 	terminalAlpha     float32
 	showDebugInfo     bool
 	keyboardShortcuts map[config.UserAction]*config.KeyCombination
+	resizeLock        *sync.Mutex
 }
 
 func New(config *config.Config, terminal *terminal.Terminal, logger *zap.SugaredLogger) (*GUI, error) {
@@ -51,6 +53,7 @@ func New(config *config.Config, terminal *terminal.Terminal, logger *zap.Sugared
 		fontScale:         14.0,
 		terminalAlpha:     1,
 		keyboardShortcuts: shortcuts,
+		resizeLock:        &sync.Mutex{},
 	}, nil
 }
 
@@ -65,6 +68,9 @@ func (gui *GUI) scale() float32 {
 // can only be called on OS thread
 func (gui *GUI) resize(w *glfw.Window, width int, height int) {
 
+	gui.resizeLock.Lock()
+	defer gui.resizeLock.Unlock()
+
 	gui.logger.Debugf("Initiating GUI resize to %dx%d", width, height)
 
 	gui.width = width