Lock focus on multiline text edit

egui/src/memory.rs

@@ -128,8 +128,12 @@ pub(crate) struct Focus {
     /// The last widget interested in focus.
     last_interested: Option<Id>,
 
+    /// Set at the beginning of the frame, set to `false` when "used".
+    is_focus_locked: bool,
+
     /// Set at the beginning of the frame, set to `false` when "used".
     pressed_tab: bool,
+
     /// Set at the beginning of the frame, set to `false` when "used".
     pressed_shift_tab: bool,
 }
@@ -195,6 +199,7 @@ impl Focus {
                 modifiers,
             } = event
             {
+                if !self.is_focus_locked {
                     if modifiers.shift {
                         self.pressed_shift_tab = true;
                     } else {
@@ -203,6 +208,7 @@ impl Focus {
                 }
             }
         }
+    }
 
     pub(crate) fn end_frame(&mut self, used_ids: &epaint::ahash::AHashMap<Id, Pos2>) {
         if let Some(id) = self.id {
@@ -225,11 +231,11 @@ impl Focus {
             self.id = Some(id);
             self.give_to_next = false;
         } else if self.id == Some(id) {
-            if self.pressed_tab {
+            if self.pressed_tab && !self.is_focus_locked {
                 self.id = None;
                 self.give_to_next = true;
                 self.pressed_tab = false;
-            } else if self.pressed_shift_tab {
+            } else if self.pressed_shift_tab && !self.is_focus_locked {
                 self.id_next_frame = self.last_interested; // frame-delay so gained_focus works
                 self.pressed_shift_tab = false;
             }
@@ -287,14 +293,22 @@ impl Memory {
         self.interaction.focus.id == Some(id)
     }
 
+    pub(crate) fn lock_focus(&mut self, id: Id) {
+        if self.had_focus_last_frame(id) && self.has_focus(id) {
+            self.interaction.focus.is_focus_locked = true;
+        }
+    }
+
     /// Give keyboard focus to a specific widget
     pub fn request_focus(&mut self, id: Id) {
         self.interaction.focus.id = Some(id);
+        self.interaction.focus.is_focus_locked = false;
     }
 
     pub fn surrender_focus(&mut self, id: Id) {
         if self.interaction.focus.id == Some(id) {
             self.interaction.focus.id = None;
+            self.interaction.focus.is_focus_locked = false;
         }
     }
 

egui/src/widgets/text_edit.rs

@@ -383,6 +383,10 @@ impl<'t> TextEdit<'t> {
         }
 
         if ui.memory().has_focus(id) && enabled {
+            if multiline {
+                ui.memory().lock_focus(id);
+            }
+
             let mut cursorp = state
                 .cursorp
                 .map(|cursorp| {
@@ -438,6 +442,19 @@ impl<'t> TextEdit<'t> {
                             None
                         }
                     }
+                    Event::Key {
+                        key: Key::Tab,
+                        pressed: true,
+                        ..
+                    } => {
+                        if multiline {
+                            let mut ccursor = delete_selected(text, &cursorp);
+                            insert_text(&mut ccursor, text, "\t");
+                            Some(CCursorPair::one(ccursor))
+                        } else {
+                            None
+                        }
+                    }
                     Event::Key {
                         key: Key::Enter,
                         pressed: true,