@@ -34,6 +34,7 @@ type standardRenderer struct {
3434 ticker * time.Ticker
3535 done chan struct {}
3636 lastRender string
37+ lastRenderedLines []string
3738 linesRendered int
3839 useANSICompressor bool
3940 once sync.Once
@@ -174,7 +175,6 @@ func (r *standardRenderer) flush() {
174175 }
175176
176177 newLines := strings .Split (r .buf .String (), "\n " )
177- oldLines := strings .Split (r .lastRender , "\n " )
178178
179179 // If we know the output's height, we can use it to determine how many
180180 // lines we can render. We drop lines from the top of the render buffer if
@@ -184,7 +184,6 @@ func (r *standardRenderer) flush() {
184184 newLines = newLines [len (newLines )- r .height :]
185185 }
186186
187- numLinesThisFlush := len (newLines )
188187 flushQueuedMessages := len (r .queuedMessageLines ) > 0 && ! r .altScreenActive
189188
190189 if flushQueuedMessages {
@@ -210,7 +209,7 @@ func (r *standardRenderer) flush() {
210209 // Paint new lines.
211210 for i := 0 ; i < len (newLines ); i ++ {
212211 canSkip := ! flushQueuedMessages && // Queuing messages triggers repaint -> we don't have access to previous frame content.
213- len (oldLines ) > i && oldLines [i ] == newLines [i ] // Previously rendered line is the same.
212+ len (r . lastRenderedLines ) > i && r . lastRenderedLines [i ] == newLines [i ] // Previously rendered line is the same.
214213
215214 if _ , ignore := r .ignoreLines [i ]; ignore || canSkip {
216215 // Unless this is the last line, move the cursor down.
@@ -257,11 +256,11 @@ func (r *standardRenderer) flush() {
257256 }
258257
259258 // Clearing left over content from last render.
260- if r .linesRendered > numLinesThisFlush {
259+ if r .linesRendered > len ( newLines ) {
261260 buf .WriteString (ansi .EraseScreenBelow )
262261 }
263262
264- r .linesRendered = numLinesThisFlush
263+ r .linesRendered = len ( newLines )
265264
266265 // Make sure the cursor is at the start of the last line to keep rendering
267266 // behavior consistent.
@@ -276,6 +275,11 @@ func (r *standardRenderer) flush() {
276275
277276 _ , _ = r .out .Write (buf .Bytes ())
278277 r .lastRender = r .buf .String ()
278+
279+ // Save previously rendered lines for comparison in the next render. If we
280+ // don't do this, we can't skip rendering lines that haven't changed.
281+ // See https://github.com/charmbracelet/bubbletea/pull/1233
282+ r .lastRenderedLines = newLines
279283 r .buf .Reset ()
280284}
281285
@@ -299,6 +303,7 @@ func (r *standardRenderer) write(s string) {
299303
300304func (r * standardRenderer ) repaint () {
301305 r .lastRender = ""
306+ r .lastRenderedLines = nil
302307}
303308
304309func (r * standardRenderer ) clearScreen () {
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