diff --git a/src/main/java/com/gregor/jprototerm/GhosttyTerminalRenderer.java b/src/main/java/com/gregor/jprototerm/GhosttyTerminalRenderer.java
index 471d302..088dc47 100644
--- a/src/main/java/com/gregor/jprototerm/GhosttyTerminalRenderer.java
+++ b/src/main/java/com/gregor/jprototerm/GhosttyTerminalRenderer.java
@@ -101,7 +101,9 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
             if (dirty == DIRTY_FULL) {
                 software.paintFullOrShifted(gc, target.snapshotFull(), px, py, width, height, active);
             } else if (dirty == DIRTY_PARTIAL) {
-                if (snapshot != null && snapshot.renderRows().size() == snapshot.rows()) {
+                if (!software.canPaintDirty(snapshot)) {
+                    software.paintFullOrShifted(gc, target.snapshotFull(), px, py, width, height, active);
+                } else if (snapshot != null && snapshot.renderRows().size() == snapshot.rows()) {
                     software.paintFullOrShifted(gc, snapshot, px, py, width, height, active);
                 } else {
                     software.paintDirty(gc, snapshot, px, py, width, height, active);
@@ -679,10 +681,16 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
         private long[] rowHashes = new long[0];
         private CursorState lastCursor = CursorState.none();
         private GlyphCache glyphs;
+        private boolean valid;
 
         private void invalidate() {
             rowHashes = new long[0];
             lastCursor = CursorState.none();
+            valid = false;
+        }
+
+        private boolean canPaintDirty(RenderStateSnapshot snapshot) {
+            return valid && snapshot != null && rowHashes.length == snapshot.rows();
         }
 
         private void paintFull(GraphicsContext gc, RenderStateSnapshot snapshot,
@@ -693,6 +701,7 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
                 paintSnapshot(snapshot);
                 drawCursor(snapshot);
                 rememberSnapshot(snapshot);
+                valid = true;
             } else {
                 invalidate();
             }
@@ -730,6 +739,7 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
                 }
             }
             lastCursor = cursor;
+            valid = true;
             drawCursor(snapshot);
             drawBorder(active);
             present(gc, px, py);
@@ -738,14 +748,9 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
         private void paintDirty(GraphicsContext gc, RenderStateSnapshot snapshot,
                 double px, double py, double paneWidth, double paneHeight, boolean active) {
             ensure(paneWidth, paneHeight);
-            if (snapshot == null) {
+            if (!canPaintDirty(snapshot)) {
                 return;
             }
-            if (rowHashes.length != snapshot.rows()) {
-                paintFull(gc, snapshot, px, py, paneWidth, paneHeight, active);
-                return;
-            }
-
             CursorState cursor = CursorState.from(snapshot);
             int oldCursorRow = lastCursor.viewportRow();
             int newCursorRow = cursor.viewportRow();
@@ -766,6 +771,7 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
             }
             repaintCursorRow(snapshot, newCursorRow, repainted);
             lastCursor = cursor;
+            valid = true;
             drawCursor(snapshot);
             drawBorder(active);
             present(gc, px, py);
@@ -856,13 +862,11 @@ final class GhosttyTerminalRenderer extends TerminalRenderer {
                     continue;
                 }
                 int score = 0;
-                int overlap = 0;
                 for (int row = 0; row < rows; row++) {
                     int previous = row - delta;
                     if (previous < 0 || previous >= rows) {
                         continue;
                     }
-                    overlap++;
                     if (currentHashes[row] == rowHashes[previous]) {
                         score++;
                     }