Clarify grid autobreak behavior

tests/test_step3_widget_renderer.py

@@ -107,6 +107,20 @@ def test_grid_auto_reduces_columns_to_parent_width(dpg_context: None) -> None:
     assert len(children[0]) == 2
     assert len(children[1]) == 3
     assert [len(_children(row)[1]) for row in children[1]] == [2, 2, 1]
+    assert 0 < get_gauge_state("narrow_metric_0").config.width < 190
+
+
+def test_grid_auto_columns_uses_available_width(dpg_context: None) -> None:
+    with dpg.window(label="Auto", width=640), dpgg.gauge_grid(
+        tag="auto_grid", columns="auto", min_column_width=180
+    ):
+        for index in range(7):
+            dpgg.digital_gauge(tag=f"auto_metric_{index}", value=index, height=60)
+
+    children = _children("auto_grid")
+    assert len(children[0]) == 3
+    assert len(children[1]) == 3
+    assert [len(_children(row)[1]) for row in children[1]] == [3, 3, 1]
 
 
 def test_grid_routes_panels_without_stealing_panel_children(dpg_context: None) -> None: