diff --git a/crates/ui-egui/src/panels/comp_settings.rs b/crates/ui-egui/src/panels/comp_settings.rs
index f06a069e8..0d07afd94 100644
--- a/crates/ui-egui/src/panels/comp_settings.rs
+++ b/crates/ui-egui/src/panels/comp_settings.rs
@@ -246,36 +246,18 @@ fn matches(d: &CompDraft, w: u32, h: u32, par: f64, fps: f64) -> bool {
     w == d.width && h == d.height && (par - d.pixel_aspect).abs() < 1e-3 && (fps - d.fps).abs() < 1e-3
 }
 
-/// Draw the dialog. Returns `Some(params)` when OK is pressed, `Some(Null)` on Cancel. `custom`
-/// are the presets the user saved; saving or deleting one pushes its engine command to `cmds`.
-pub fn show(
+/// The controls of one tab.
+fn tab_body(
     ui: &mut egui::Ui,
+    tab: Tab,
     d: &mut CompDraft,
     t: &Tokens,
     auto: &mut Registry,
     custom: &[CompPreset],
     cmds: &mut Vec<(&'static str, serde_json::Value)>,
-) -> Option<serde_json::Value> {
-    let mut out = None;
-    ui.horizontal(|ui| {
-        ui.label(tr("Composition Name:"));
-        let r = ui.add(egui::TextEdit::singleline(&mut d.name).desired_width(300.0));
-        crate::widgets::focus_on_open(ui.ctx(), &r, &d.name);
-        auto.add("dialog.comp.name", r.rect, "Composition Name");
-    });
-    ui.add_space(8.0);
-    ui.horizontal(|ui| {
-        for (tab, label, key) in [(Tab::Basic, "Basic", "basic"), (Tab::Advanced, "Advanced", "advanced"), (Tab::Renderer, "3D Renderer", "renderer")] {
-            let r = ui.selectable_label(d.tab == tab, label);
-            auto.add(&format!("dialog.comp.tab.{key}"), r.rect, label);
-            if r.clicked() {
-                d.tab = tab;
-            }
-        }
-    });
-    ui.separator();
+) {
     let rate = FrameRate::from_f64(d.fps);
-    match d.tab {
+    match tab {
         Tab::Basic => {
             egui::Grid::new("comp-basic").num_columns(2).spacing([12.0, 9.0]).show(ui, |ui| {
                 ui.label(tr("Preset:"));
@@ -485,6 +467,54 @@ pub fn show(
             });
         }
     }
+}
+
+/// The height `tab` would take at `top`, from laying it out unseen: it follows the font, the
+/// language and the scale. Nothing it registers or changes is kept.
+fn tab_height(ui: &mut egui::Ui, tab: Tab, d: &CompDraft, t: &Tokens, custom: &[CompPreset], top: f32) -> f32 {
+    let rect = egui::Rect::from_min_size(egui::pos2(ui.max_rect().left(), top), vec2(ui.max_rect().width(), 0.0));
+    let mut child = ui.new_child(egui::UiBuilder::new().max_rect(rect).id_salt("comp-tab-measure").invisible());
+    tab_body(&mut child, tab, &mut d.clone(), t, &mut Registry::default(), custom, &mut Vec::new());
+    child.cursor().top() - top
+}
+
+/// Draw the dialog. Returns `Some(params)` when OK is pressed, `Some(Null)` on Cancel. `custom`
+/// are the presets the user saved; saving or deleting one pushes its engine command to `cmds`.
+pub fn show(
+    ui: &mut egui::Ui,
+    d: &mut CompDraft,
+    t: &Tokens,
+    auto: &mut Registry,
+    custom: &[CompPreset],
+    cmds: &mut Vec<(&'static str, serde_json::Value)>,
+) -> Option<serde_json::Value> {
+    let mut out = None;
+    ui.horizontal(|ui| {
+        ui.label(tr("Composition Name:"));
+        let r = ui.add(egui::TextEdit::singleline(&mut d.name).desired_width(300.0));
+        crate::widgets::focus_on_open(ui.ctx(), &r, &d.name);
+        auto.add("dialog.comp.name", r.rect, "Composition Name");
+    });
+    ui.add_space(8.0);
+    ui.horizontal(|ui| {
+        for (tab, label, key) in [(Tab::Basic, "Basic", "basic"), (Tab::Advanced, "Advanced", "advanced"), (Tab::Renderer, "3D Renderer", "renderer")] {
+            let r = ui.selectable_label(d.tab == tab, label);
+            auto.add(&format!("dialog.comp.tab.{key}"), r.rect, label);
+            if r.clicked() {
+                d.tab = tab;
+            }
+        }
+    });
+    ui.separator();
+    // Every tab takes the height of the tallest one, so Cancel and OK stay put between tabs.
+    let body_top = ui.cursor().top();
+    tab_body(ui, d.tab, d, t, auto, custom, cmds);
+    let shown = ui.cursor().top() - body_top;
+    let tallest = [Tab::Basic, Tab::Advanced, Tab::Renderer]
+        .into_iter()
+        .filter(|tab| *tab != d.tab)
+        .fold(shown, |h, tab| h.max(tab_height(ui, tab, d, t, custom, body_top)));
+    ui.add_space((tallest - shown).max(0.0));
     ui.add_space(14.0);
     ui.horizontal(|ui| {
         ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
diff --git a/crates/ui-egui/tests/it/ui_comp_presets.rs b/crates/ui-egui/tests/it/ui_comp_presets.rs
index 0b0b30720..9e71f8fd7 100644
--- a/crates/ui-egui/tests/it/ui_comp_presets.rs
+++ b/crates/ui-egui/tests/it/ui_comp_presets.rs
@@ -83,3 +83,23 @@ fn a_preset_name_cannot_be_a_built_in_one() {
     assert!(h.state().auto.find("dialog.comp.presetName").is_none());
     assert!(preset_names(&h).is_empty());
 }
+
+/// Cancel and OK stay where they are when switching between Basic, Advanced and 3D Renderer,
+/// at any interface scale: the tabs' heights are measured, not assumed.
+#[test]
+fn composition_settings_buttons_stay_put_between_tabs() {
+    for zoom in [1.0, 1.3] {
+        let mut h = harness();
+        h.ctx.set_zoom_factor(zoom);
+        h.run_steps(3);
+        open_settings(&mut h);
+        let rects = |h: &Harness<'_, EffectcraftApp>| {
+            ["dialog.comp.ok", "dialog.comp.cancel", "dialog.comp.name"].map(|id| h.state().auto.find(id).unwrap_or_else(|| panic!("no {id}")).rect)
+        };
+        let basic = rects(&h);
+        for tab in ["advanced", "renderer", "basic"] {
+            click(&mut h, &format!("dialog.comp.tab.{tab}"));
+            assert_eq!(rects(&h), basic, "{tab} at {zoom}x");
+        }
+    }
+}