Fix panic when dragging window between monitors of different pixels_per_point

crates/egui/src/context.rs

@@ -2171,12 +2171,15 @@ impl Context {
 
         self.write(|ctx| {
             let tessellation_options = ctx.memory.options.tessellation_options;
-            let texture_atlas = ctx
-                .fonts
-                .get(&pixels_per_point.into())
-                .expect("tessellate called with a different pixels_per_point than the font atlas was created with. \
-                         You should use egui::FullOutput::pixels_per_point when tessellating.")
-                .texture_atlas();
+            let texture_atlas = match ctx.fonts.get(&pixels_per_point.into()) {
+                Some(fonts) => fonts.texture_atlas(),
+                None => {
+                    ctx.fonts.iter().next()
+                    .expect("tessellate called with a different pixels_per_point than the font atlas was created with. \
+                    You should use egui::FullOutput::pixels_per_point when tessellating.")
+                    .1.texture_atlas()
+                }
+            };
             let (font_tex_size, prepared_discs) = {
                 let atlas = texture_atlas.lock();
                 (atlas.size(), atlas.prepared_discs())

crates/egui/src/layers.rs

@@ -149,6 +149,10 @@ impl PaintList {
     /// and then later setting it using `paint_list.set(idx, cr, frame);`.
     #[inline(always)]
     pub fn set(&mut self, idx: ShapeIdx, clip_rect: Rect, shape: Shape) {
+        if self.0.len() <= idx.0 {
+            self.add(clip_rect, Shape::Noop);
+        }
+
         self.0[idx.0] = ClippedShape { clip_rect, shape };
     }