diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 3925894..07b4aaf 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -74,7 +74,7 @@ jobs:
           robot
           --outputdir results/playground
           --variable BROWSER:headlesschrome
-          tests/_diagnostic.robot
+          tests/playground
 
       - name: Upload playground test results
         if: always()
diff --git a/resources/pages/playground_page.resource b/resources/pages/playground_page.resource
index 7c36121..bd1e338 100644
--- a/resources/pages/playground_page.resource
+++ b/resources/pages/playground_page.resource
@@ -23,6 +23,7 @@ ${CLASS_ATTRIBUTE_TARGET_BUTTON}        css:.btn-primary
 
 # Hidden Layers
 ${HIDING_BUTTON}                        css:#greenButton
+${HIDDEN_BLUE_BUTTON}                   css:#blueButton
 
 # Load Delay
 ${LOAD_DELAY_BUTTON}                    css:.btn.btn-primary
@@ -75,7 +76,7 @@ ${SAMPLE_APP_STATUS_MESSAGE}            css:#loginstatus
 ${SAMPLE_APP_VALID_PASSWORD}            pwd
 
 # Mouse Over
-${MOUSE_OVER_LINK}                      xpath://a[@class="text-primary" and text()="Click me"]
+${MOUSE_OVER_LINK}                      xpath://a[text()="Click me"]
 ${MOUSE_OVER_CLICK_COUNT}               css:#clickCount
 ${MOUSE_OVER_BUTTON_LINK}               xpath://a[@class="text-primary" and text()="Link Button"]
 ${MOUSE_OVER_BUTTON_CLICK_COUNT}        css:#clickButtonCount
@@ -86,6 +87,7 @@ ${NBSP_BUTTON_EXACT_TEXT}               xpath://button[text()="My Button"]
 
 # Overlapped Element
 ${OVERLAPPED_NAME_FIELD}                css:#name
+${OVERLAPPED_NAME_FIELD_SELECTOR}       input#name
 
 # Shadow DOM
 ${SHADOW_HOST}                          guid-generator
@@ -203,18 +205,13 @@ Wait Until Animation Stops
     Fail    Element '${locator}' never stopped moving.
 
 Set Value Via Javascript
-    [Documentation]    Sets an input's value directly through JavaScript and dispatches an
-    ...                input event so the page's own listeners see the change. Used for the
-    ...                Overlapped Element challenge, where the field is covered by another
-    ...                element and native Selenium keystrokes never register.
-    [Arguments]    ${locator}    ${value}
-    ${element}=    Get WebElement    ${locator}
-    Execute Javascript
-    ...    arguments[0].value = arguments[1];
-    ...    arguments[0].dispatchEvent(new Event('input', {bubbles: true}));
-    ...    ARGUMENTS
-    ...    ${element}
-    ...    ${value}
+    [Documentation]    Sets an input's value directly through JavaScript. Used for the
+    ...                Overlapped Element challenge, where a permanently positioned
+    ...                covering element blocks native Selenium clicks and keystrokes; the
+    ...                field carries no input/change listeners, so a plain property
+    ...                assignment (confirmed against the live page) is sufficient.
+    [Arguments]    ${selector}    ${value}
+    Execute Javascript    document.querySelector('${selector}').value = '${value}';
 
 Get Row Cell Values
     [Documentation]    Reads the ARIA role="row" elements of the Dynamic Table challenge
diff --git a/tests/_diagnostic.robot b/tests/_diagnostic.robot
deleted file mode 100644
index c36f8f0..0000000
--- a/tests/_diagnostic.robot
+++ /dev/null
@@ -1,62 +0,0 @@
-*** Settings ***
-Documentation       Temporary diagnostic, round 6: four assertions have now failed twice on
-...                 guessed fixes (Hidden Layers' id-swap, Sample App's valid password,
-...                 Mouse Over's link replacement, Overlapped's JS value-setting) -- this
-...                 gets real evidence instead of guessing a third time. Not part of the
-...                 portfolio.
-Resource            ../resources/pages/playground_page.resource
-Suite Setup         Open Browser    about:blank    ${BROWSER}
-Suite Teardown      Close All Browsers
-Test Tags           smoke
-
-
-*** Test Cases ***
-Dump Hidden Layers After Click
-    Go To Playground Page    hiddenlayers
-    ${before}=    Execute Javascript    return document.querySelector('#spa').outerHTML;
-    Log    SPA BEFORE CLICK: ${before}    console=True
-    Click Element    ${HIDING_BUTTON}
-    ${after}=    Execute Javascript    return document.querySelector('#spa').outerHTML;
-    Log    SPA AFTER CLICK: ${after}    console=True
-
-Dump Sample App Login Attempt
-    Go To Playground Page    sampleapp
-    Input Text    ${SAMPLE_APP_USERNAME_FIELD}    Michelle
-    Input Text    ${SAMPLE_APP_PASSWORD_FIELD}    pwd
-    ${username_value}=    Get Element Attribute    ${SAMPLE_APP_USERNAME_FIELD}    value
-    ${password_value}=    Get Element Attribute    ${SAMPLE_APP_PASSWORD_FIELD}    value
-    Log    FIELD VALUES BEFORE SUBMIT: username=${username_value} password=${password_value}    console=True
-    Click Button    ${SAMPLE_APP_LOGIN_BUTTON}
-    ${status}=    Get Text    ${SAMPLE_APP_STATUS_MESSAGE}
-    Log    STATUS AFTER SUBMIT: ${status}    console=True
-
-Dump Mouse Over Link Structure
-    Go To Playground Page    mouseover
-    ${before}=    Execute Javascript
-    ...    return Array.from(document.querySelectorAll('a')).map(function(a) {
-    ...    return 'outerHTML=' + a.outerHTML;
-    ...    }).join(' || ');
-    Log    LINKS BEFORE HOVER: ${before}    console=True
-    Mouse Over    css:a.text-primary
-    Sleep    300ms
-    ${after}=    Execute Javascript
-    ...    return Array.from(document.querySelectorAll('a')).map(function(a) {
-    ...    return 'outerHTML=' + a.outerHTML;
-    ...    }).join(' || ');
-    Log    LINKS AFTER HOVER: ${after}    console=True
-
-Dump Overlapped Field Framework And Direct Js Set
-    Go To Playground Page    overlapped
-    ${framework}=    Execute Javascript
-    ...    var root = document.getElementById('root') || document.getElementById('app') || document.body.firstElementChild;
-    ...    return 'reactroot=' + (root && !!Object.keys(root).find(function(k) { return k.startsWith('__reactContainer') || k.startsWith('_reactRootContainer'); })) + ' outerHTML=' + document.querySelector('#name').outerHTML;
-    Log    OVERLAPPED FIELD INFO: ${framework}    console=True
-    ${direct_result}=    Execute Javascript
-    ...    var el = document.querySelector('#name');
-    ...    el.value = 'Michelle Austria';
-    ...    el.dispatchEvent(new Event('input', {bubbles: true}));
-    ...    return 'immediately after set: ' + el.value;
-    Log    DIRECT SET RESULT: ${direct_result}    console=True
-    Sleep    300ms
-    ${value_after_wait}=    Get Element Attribute    css:#name    value
-    Log    VALUE AFTER 300MS WAIT: ${value_after_wait}    console=True
diff --git a/tests/playground/ui_testing_playground.robot b/tests/playground/ui_testing_playground.robot
index 82f5665..8df725e 100644
--- a/tests/playground/ui_testing_playground.robot
+++ b/tests/playground/ui_testing_playground.robot
@@ -44,16 +44,14 @@ Class Attribute Target Button Should Be Clicked By Its Unique Class
     ${alert_message}=    Handle Alert    action=ACCEPT
     Should Be Equal    ${alert_message}    Primary button pressed
 
-Clicking The Green Button Should Swap In A Different Layer
-    [Documentation]    The button under #spa is replaced by a different element after the
-    ...    first click, demonstrating a DOM-caching pitfall: a second click against a
-    ...    previously located WebElement reference would silently hit a stale layer.
+Clicking The Green Button Should Add A Covering Layer On Top
+    [Documentation]    Clicking the green button doesn't remove it -- it stacks a second,
+    ...    higher z-index layer with a blue button directly on top, so a second click at
+    ...    the same coordinates would silently hit the new layer instead.
     Go To Playground Page    hiddenlayers
     Wait Until Element Is Visible    ${HIDING_BUTTON}
     Click Element    ${HIDING_BUTTON}
-    ${new_id}=    Execute Javascript    return document.querySelector('#spa button').id;
-    Should Not Be Equal    ${new_id}    greenButton
-    ...    msg=Hidden Layers should swap in a different button after the first click.
+    Page Should Contain Element    ${HIDDEN_BLUE_BUTTON}
 
 Button Appearing After Delay Should Eventually Become Clickable
     [Documentation]    The button doesn't exist in a clickable state until the server
@@ -163,6 +161,7 @@ Sample App Should Log In With The Valid Password And Reject An Invalid One
     Input Text    ${SAMPLE_APP_PASSWORD_FIELD}    wrong-password
     Click Button    ${SAMPLE_APP_LOGIN_BUTTON}
     Element Text Should Be    ${SAMPLE_APP_STATUS_MESSAGE}    Invalid username/password
+    Input Text    ${SAMPLE_APP_USERNAME_FIELD}    Michelle
     Input Text    ${SAMPLE_APP_PASSWORD_FIELD}    ${SAMPLE_APP_VALID_PASSWORD}
     Click Button    ${SAMPLE_APP_LOGIN_BUTTON}
     Element Text Should Be    ${SAMPLE_APP_STATUS_MESSAGE}    Welcome, Michelle!
@@ -187,11 +186,11 @@ Non Breaking Space Button Should Not Match An Exact Text Locator
     Click Button    ${NBSP_BUTTON}
 
 Overlapped Name Field Should Accept Text Set Through Javascript
-    [Documentation]    The field is covered by another element, so native Selenium
-    ...    keystrokes never register; setting the value directly through JavaScript and
-    ...    dispatching an input event is the documented workaround.
+    [Documentation]    A permanently positioned element covers the field, so native
+    ...    Selenium clicks and keystrokes are intercepted; setting the value directly
+    ...    through JavaScript is the workaround.
     Go To Playground Page    overlapped
-    Set Value Via Javascript    ${OVERLAPPED_NAME_FIELD}    Michelle Austria
+    Set Value Via Javascript    ${OVERLAPPED_NAME_FIELD_SELECTOR}    Michelle Austria
     ${value}=    Get Element Attribute    ${OVERLAPPED_NAME_FIELD}    value
     Should Be Equal    ${value}    Michelle Austria