docs: document Gradio 6.12 tab-switching bug + workaround

- README: add Known Issues section describing the Dataframe component
crash that silently blocks tab navigation after Walk results load,
with workaround (refresh page before switching tabs)
- app.py: add tip note below Walk feature table pointing users to the
workaround

README.md

@@ -41,6 +41,26 @@ pip install -r demo/requirements.txt
 python demo/app.py
 ```
 
+## Known Issues
+
+### Tab navigation stops working after running Walk Explorer
+
+**What happens:** After running a query in the Walk Explorer tab and results appear
+in the feature table, clicking other tabs (Knowledge Probe, LQL Console, etc.) may
+silently fail — the tab appears not to switch.
+
+**Root cause:** Gradio 6.12 bug. A `TypeError` in the internal Dataframe component
+(`Index-BGETwOir.js: Cannot read properties of undefined (reading '0')`) fires during
+the Svelte reactive re-render triggered by the tab switch. The error is swallowed
+silently, leaving the UI stuck on Walk Explorer.
+
+**Workaround:** Refresh the page (F5 / ⌘R) and navigate to the desired tab
+*before* running Walk. All tabs function correctly on a fresh page load.
+The bug only appears after Walk results populate the feature table.
+
+**Affected version:** Gradio 6.12.0 (pinned in `requirements.txt`).
+Upgrading Gradio may resolve it once the upstream issue is fixed.
+
 ## Credits
 
 - **LARQL / LQL / vindex format:** Chris Hayuk ([@chrishayuk](https://github.com/chrishayuk))

app.py

@@ -413,6 +413,13 @@ with gr.Blocks(title="LARQL Explorer") as demo:
                 wrap=True,
                 column_widths=["80px", "90px", "80px", "110px", "140px", "80px", "auto"],
             )
+            gr.Markdown(
+                "_💡 **Tip:** If clicking other tabs stops working after running Walk, "
+                "refresh the page (F5) and navigate to the desired tab first. "
+                "This is a Gradio 6.12 interaction bug that only appears after "
+                "the feature table is populated._",
+                visible=True,
+            )
 
             walk_btn.click(
                 do_walk,