Restore TextArea size fix, conditional on !clip_text

crates/egui/src/widgets/text_edit/builder.rs

@@ -1,5 +1,6 @@
 use std::sync::Arc;
 
+use emath::Rect;
 use epaint::text::{cursor::CCursor, Galley, LayoutJob};
 
 use crate::{
@@ -562,7 +563,7 @@ impl TextEdit<'_> {
             Sense::hover()
         };
         let mut response = ui.interact(outer_rect, id, sense);
-        response.intrinsic_size = Some(Vec2::new(desired_width, desired_outer_size.y));
+        response.intrinsic_size = Some(Vec2::new(desired_width, desired_outer_size.y)); // HERE!!!
 
         // Don't sent `OutputEvent::Clicked` when a user presses the space bar
         response.flags -= response::Flags::FAKE_PRIMARY_CLICKED;
@@ -722,6 +723,19 @@ impl TextEdit<'_> {
                 }
             }
 
+            if !clip_text {
+                // Allocate additional space if edits were made this frame that changed the size. This is important so that,
+                // if there's a ScrollArea, it can properly scroll to the cursor.
+                // Condition `!clip_text` is important to avoid breaking layout for `TextEdit::singleline` (PR #5640)
+                let extra_size = galley.size() - rect.size();
+                if extra_size.x > 0.0 || extra_size.y > 0.0 {
+                    ui.allocate_rect(
+                        Rect::from_min_size(outer_rect.max, extra_size),
+                        Sense::hover(),
+                    );
+                }
+            }
+
             painter.galley(galley_pos, galley.clone(), text_color);
 
             if has_focus {