docs(dashboards): document drag-to-place for dashboard widgets (CUB-3179) (#11555)

Author: mngr

docs-mintlify/docs/explore-analyze/dashboards/widgets/index.mdx

@@ -15,7 +15,20 @@ The dashboard builder supports the following widget types:
 - [AI summary](/docs/explore-analyze/dashboards/widgets/ai-summary) — Generate narrative summaries of dashboard data on demand
 - [Spacer & Divider](/docs/explore-analyze/dashboards/widgets/layout) — Non-data layout elements for whitespace and section breaks (in preview)
 
-In the dashboard builder, add widgets using the toolbar at the top of the canvas: pick reports from the **Charts** picker to add charts, use the **Add Widgets** menu for text, AI summaries, and layout elements, or add a **Filter** or **Time Granularity** control from the **Add Controls** group.
+## Adding widgets
+
+Add widgets from the toolbar at the top of the dashboard builder: pick reports from the **Charts** picker to add charts, use the **Add Widgets** menu for text, AI summaries, and layout elements, or add a **Filter** or **Time Granularity** control from the **Add Controls** group.
+
+Each toolbar item can be added in two ways:
+
+- **Click** it to drop the widget into the first open spot on the canvas.
+- **Drag** it from the toolbar onto the canvas to place it exactly where you want. As you drag, a full-size placeholder previews the widget's footprint and the surrounding widgets reflow to open a slot; release to drop it there. Dragging is especially handy on dense dashboards, where clicking would otherwise place the new widget far down the page.
+
+<Warning>
+
+Dragging a toolbar item to place it exactly (drag-to-place) is currently in preview, and the behavior may still change. Reach out to the [Cube support team](/admin/account-billing/support) to activate it for your account. Clicking to add a widget is available to everyone.
+
+</Warning>
 
 ## Arranging widgets