diff --git a/src/gui/src/helpers/shareRecipientPicker.js b/src/gui/src/helpers/shareRecipientPicker.js
index b7271ee4a..7fcf9f19c 100644
--- a/src/gui/src/helpers/shareRecipientPicker.js
+++ b/src/gui/src/helpers/shareRecipientPicker.js
@@ -163,20 +163,26 @@ export default function shareRecipientPicker ({
     const MIN_HEIGHT = 120;
 
     /**
-     * The box the list has to stay inside — the nearest ancestor that clips,
-     * which is the modal's scrolling body in one dialog and the window in the
-     * other. Falls back to the viewport.
+     * The box the list has to stay inside: the viewport, narrowed to the
+     * nearest ancestor that clips — the modal's scrolling body in one dialog
+     * and the window's in the other. Both bound it, and a dialog dragged low
+     * on a short screen has a clipping ancestor that reaches past the fold.
      */
     const clip_box = () => {
+        const bottom = window.innerHeight || 0;
         let el = $row.get(0)?.parentElement;
         while ( el && el !== document.body ) {
             const style = getComputedStyle(el);
             if ( /auto|scroll|hidden/.test(`${style.overflowY}${style.overflowX}`) ) {
-                return el.getBoundingClientRect();
+                const box = el.getBoundingClientRect();
+                return {
+                    top: Math.max(box.top, 0),
+                    bottom: Math.min(box.bottom, bottom),
+                };
             }
             el = el.parentElement;
         }
-        return { top: 0, bottom: window.innerHeight || 0 };
+        return { top: 0, bottom };
     };
 
     /**
diff --git a/src/gui/src/helpers/shareRecipientPicker.test.js b/src/gui/src/helpers/shareRecipientPicker.test.js
index 4160d35b5..bcd533bd5 100644
--- a/src/gui/src/helpers/shareRecipientPicker.test.js
+++ b/src/gui/src/helpers/shareRecipientPicker.test.js
@@ -90,10 +90,13 @@ beforeEach(() => {
     };
 });
 
+const default_viewport_height = 768;
+
 afterEach(() => {
     mounted.forEach((picker) => picker.destroy());
     mounted = [];
     document.body.innerHTML = '';
+    window.innerHeight = default_viewport_height;
 });
 
 describe('wiring onto the field', () => {
@@ -161,6 +164,38 @@ describe('opening the list', () => {
         expect($('.share-suggest-list').get(0).style.maxHeight).toMatch(/px$/);
     });
 
+    // jsdom has no layout, so the boxes `place()` measures are stubbed: a
+    // scrolling ancestor holding the row, reaching past the bottom of the
+    // screen the way a dialog dragged low on a short display does.
+    const stub_layout = ({ viewport, clip, row }) => {
+        window.innerHeight = viewport;
+        const host = $('.host').get(0);
+        host.style.overflowY = 'auto';
+        host.getBoundingClientRect = () => ({ top: clip[0], bottom: clip[1] });
+        $('.row').get(0).getBoundingClientRect = () => ({ top: row[0], bottom: row[1] });
+    };
+
+    it('caps the list at the room on screen, not the room in the dialog', async () => {
+        const { picker, $input } = mount();
+        stub_layout({ viewport: 700, clip: [200, 780], row: [480, 517] });
+        picker.setTeams([ACME]);
+        $input.trigger('click');
+        await settle();
+
+        // 700 - 517 - 24, not the 239 the clipping ancestor alone reports.
+        expect($('.share-suggest-list').get(0).style.maxHeight).toBe('159px');
+    });
+
+    it('opens upwards when what is below the field is off the screen', async () => {
+        const { picker, $input } = mount();
+        stub_layout({ viewport: 700, clip: [100, 900], row: [600, 637] });
+        picker.setTeams([ACME]);
+        $input.trigger('click');
+        await settle();
+
+        expect($('.share-suggest').hasClass('share-suggest-above')).toBe(true);
+    });
+
     it('leaves out whoever the access list already covers', async () => {
         const { picker, $input } = mount({ excluded: () => ['user:bob', 'team:t-1'] });
         picker.setTeams([ACME]);