fix: Have hovertool work across DynamicMaps elements

holoviews/plotting/bokeh/element.py

@@ -648,13 +648,18 @@ def _get_hover_data(self, data, element, dimensions=None):
         If empty initializes with no data.
 
         """
-        if 'hover' not in self.handles or self.static_source:
+        has_hover = 'hover' in self.handles
+        if not has_hover and not self.overlay_dims:
             return
 
-        for d in (dimensions or element.dimensions()):
-            dim = util.dimension_sanitizer(d.name)
-            if dim not in data:
-                data[dim] = element.dimension_values(d)
+        if has_hover and not self.static_source:
+            for d in (dimensions or element.dimensions()):
+                dim = util.dimension_sanitizer(d.name)
+                if dim not in data:
+                    data[dim] = element.dimension_values(d)
+
+        if not data:
+            return
 
         for k, v in self.overlay_dims.items():
             dim = util.dimension_sanitizer(k.name)
@@ -3596,6 +3601,14 @@ def update_frame(self, key, ranges=None, element=None):
             if not self.tabs:
                 init_kwargs['plot'] = self.handles['plot']
             self._create_dynamic_subplots(key, items, ranges, **init_kwargs)
+            if overlay_hover := self.handles.get('hover'):
+                if overlay_hover.renderers == 'auto':
+                    overlay_hover.renderers = []
+                for k, _ in items:
+                    if k in self.subplots and 'glyph_renderer' in self.subplots[k].handles:
+                        renderer = self.subplots[k].handles['glyph_renderer']
+                        if renderer not in overlay_hover.renderers:
+                            overlay_hover.renderers.append(renderer)
             if not self.overlaid and not self.tabs:
                 self._process_legend(element)
 

holoviews/tests/ui/bokeh/test_hover.py

@@ -519,6 +519,43 @@ def test_hover_heatmap_image(serve_hv, x_axis_type, y_axis_type):
     expect(tooltip).to_contain_text("z: 53")
 
 
+@pytest.mark.usefixtures("bokeh_backend")
+def test_hover_across_dynamicmaps(serve_panel):
+    data = pd.DataFrame({"x": range(2), "y": range(2), "category": ["A", "B"]})
+    el = (
+        hv.Dataset(data)
+        .to(hv.Points, kdims=["x", "y"], groupby="category")
+        .opts(tools=["hover"], size=10, show_legend=False, xlim=(-1, 3), ylim=(-1, 3), hit_dilation=100)
+    )
+    widget = pn.widgets.MultiSelect(value=["A"], options=["A", "B"])
+    dmap = hv.DynamicMap(
+        lambda value: el.get(value).overlay(),
+        streams=[widget.param.value]
+    )
+    col = pn.Column(widget, dmap)
+    page = serve_panel(col)
+
+    hv_plot = page.locator(".bk-events")
+    expect(hv_plot).to_have_count(1)
+    bbox = hv_plot.bounding_box()
+
+    for i, cat in enumerate(("A", "B")):
+        widget.value = [cat]
+        page.mouse.move(bbox["x"] + bbox["width"] / 2, bbox["y"] + bbox["height"] / 2)
+        page.mouse.up()
+        tooltip = page.locator(".bk-Tooltip")
+        expect(tooltip).to_have_count(1)
+        expect(tooltip.first).to_contain_text(f"category: {cat} x: {i} y: {i}")
+
+    widget.value = ["A", "B"]
+    page.mouse.move(bbox["x"] + bbox["width"] / 2, bbox["y"] + bbox["height"] / 2)
+    page.mouse.up()
+    tooltip = page.locator(".bk-Tooltip")
+    expect(tooltip).to_have_count(2)
+    expect(tooltip.first).to_contain_text("category: A x: 0 y: 0")
+    expect(tooltip.last).to_contain_text("category: B x: 1 y: 1")
+
+
 @pytest.mark.usefixtures("bokeh_backend")
 def test_hover_heatmap_categorical_outside_plot_area(serve_hv, caplog):
     # Test for https://github.com/holoviz/holoviews/pull/6438