docs: note on locator handler trigger (#30004)

Fixes #30003

docs/src/api/class-page.md

@@ -3156,7 +3156,7 @@ This method lets you set up a special function, called a handler, that activates
 
 Things to keep in mind:
 * When an overlay is shown predictably, we recommend explicitly waiting for it in your test and dismissing it as a part of your normal test flow, instead of using [`method: Page.addLocatorHandler`].
-* Playwright checks for the overlay every time before executing or retrying an action that requires an [actionability check](../actionability.md), or before performing an auto-waiting assertion check. When overlay is visible, Playwright calls the handler first, and then proceeds with the action/assertion.
+* Playwright checks for the overlay every time before executing or retrying an action that requires an [actionability check](../actionability.md), or before performing an auto-waiting assertion check. When overlay is visible, Playwright calls the handler first, and then proceeds with the action/assertion. Note that the handler is only called when you perform an action/assertion - if the overlay becomes visible but you don't perform any actions, the handler will not be triggered.
 * The execution time of the handler counts towards the timeout of the action/assertion that executed the handler. If your handler takes too long, it might cause timeouts.
 * You can register multiple handlers. However, only a single handler will be running at a time. Make sure the actions within a handler don't depend on another handler.
 

packages/playwright-core/types/types.d.ts

@@ -1796,7 +1796,9 @@ export interface Page {
    *   [page.addLocatorHandler(locator, handler)](https://playwright.dev/docs/api/class-page#page-add-locator-handler).
    * - Playwright checks for the overlay every time before executing or retrying an action that requires an
    *   [actionability check](https://playwright.dev/docs/actionability), or before performing an auto-waiting assertion check. When overlay
-   *   is visible, Playwright calls the handler first, and then proceeds with the action/assertion.
+   *   is visible, Playwright calls the handler first, and then proceeds with the action/assertion. Note that the
+   *   handler is only called when you perform an action/assertion - if the overlay becomes visible but you don't
+   *   perform any actions, the handler will not be triggered.
    * - The execution time of the handler counts towards the timeout of the action/assertion that executed the handler.
    *   If your handler takes too long, it might cause timeouts.
    * - You can register multiple handlers. However, only a single handler will be running at a time. Make sure the