ui: Switch to fixed containment to allow overflow

ui/src/widgets/cursor_tooltip.ts

@@ -74,6 +74,8 @@ export class CursorTooltip implements m.ClassComponent<CursorTooltipAttrs> {
         onContentMount: (portal) => {
           this.virtualElement.setPosition(globalMousePos);
           this.popper = createPopper(this.virtualElement, portal, {
+            // As for popups, escape ancestors that clip overflow
+            strategy: 'fixed',
             placement: 'right',
             modifiers: [
               {

ui/src/widgets/popup.ts

@@ -422,6 +422,9 @@ export class Popup implements m.ClassComponent<PopupAttrs> {
     };
 
     const options: Partial<OptionsGeneric<ExtendedModifiers>> = {
+      // Fixed positioning escapes ancestors that clip overflow, such as a host
+      // page's panels when the UI is embedded, and keeps the popup in the viewport
+      strategy: 'fixed',
       placement: position,
       modifiers: [
         // Move the popup away from the target allowing room for the arrow

ui/src/widgets/tooltip.ts

@@ -182,6 +182,8 @@ export class Tooltip implements m.ClassComponent<TooltipAttrs> {
     } = attrs;
 
     const options: Partial<OptionsGeneric<ExtendedModifiers>> = {
+      // As for popups, escape ancestors that clip overflow
+      strategy: 'fixed',
       placement: position,
       modifiers: [
         {