Let Esc and a click on empty space deselect Design feature and body rows

docs/HLSD/design-tab.md

@@ -134,7 +134,7 @@ contract between them is stated in code rather than spread across handlers.
 | `Transient` | a value field or a popup menu | closes it; the tool stays armed |
 | `Gesture` | an uncommitted delta — an entity being drawn, a body being dragged | reverts it; committed work is untouched |
 | `Tool` | a feature card, an armed sketch tool, a constrain session | exits it; drawn entities survive |
-| `Idle` | nothing transient | clears the selection; leaves a sketch session only if it is empty |
+| `Idle` | nothing transient | clears the selection, a Feature tree or Bodies row included; leaves a sketch session only if it is empty |
 
 `cad_escape_level()` is a `constexpr` free function over a POD of four booleans rather than a
 method on the panel, so the ordering that is the entire contract is checkable without a window,
@@ -211,7 +211,8 @@ that makes no face of its own, such as a Boolean union, answers with the bodies
 replay costs up to a recompute, so the panel finds the faces once per row and topology
 generation, off the UI thread, and only while no feature card is open. One selection is live at
 a time: a viewport pick clears the feature row and a feature row clears the viewport pick, as the
-Feature tree and Bodies list do between themselves.
+Feature tree and Bodies list do between themselves. `Esc`, a click on empty space and an
+empty rubber band all let go of it, whichever list or pick made it.
 
 ## Following the app
 

src/slic3r/GUI/CAD/DesignCanvas.cpp

@@ -899,6 +899,11 @@ void DesignCanvas::set_on_solid_selection_changed(std::function<void(int, int, i
     };
 }
 
+void DesignCanvas::set_on_empty_pick(std::function<void()> cb)
+{
+    m_sketch_tool.on_empty_pick = std::move(cb);
+}
+
 void DesignCanvas::select_body(int body)
 {
     m_sketch_tool.select_body(body);

src/slic3r/GUI/CAD/DesignCanvas.hpp

@@ -139,6 +139,7 @@ public:
                         const std::vector<bool>* visible = nullptr,
                         const std::vector<Transform3d>* xform = nullptr);
     void set_on_solid_selection_changed(std::function<void(int, int, int, int)> cb);
+    void set_on_empty_pick(std::function<void()> cb);   // a click or rubber band took nothing
     std::vector<int> selected_solid_edges() const;   // the Shift/Ctrl+click edge set, last-clicked at the end
     void select_body(int body);   // Parts-list -> highlight a whole body by index
     // Effective display colour of a body: the per-body override (Color tool) when set,

src/slic3r/GUI/CAD/DesignPanel.cpp

@@ -3826,6 +3826,12 @@ DesignPanel::DesignPanel(wxWindow* parent)
                                       : _L("Nothing selected"));
         m_status->Refresh();
     });
+    // A click on nothing drops a list row as it drops a pick. Not while a card is open: the
+    // feature being edited keeps its row.
+    m_viewport->set_on_empty_pick([this] {
+        if (m_active == Tool::None && deselect_rows())
+            set_status(StatusKind::Info, _L("Nothing selected"));
+    });
 
     // Visual Extrude gizmo (C5b): dragging/editing the in-canvas depth arrow writes the
     // matching spin field and re-previews (which re-feeds the gizmo with the new depth).
@@ -7526,6 +7532,16 @@ int DesignPanel::tree_body_selection() const
     return m_parts == nullptr ? -1 : m_parts->selection();
 }
 
+// Unselect the Feature tree and Bodies rows; each list's on_select clears what its row lit. True
+// if a row was selected.
+bool DesignPanel::deselect_rows()
+{
+    const bool any = (m_tree && tree_selection() != wxNOT_FOUND) || tree_body_selection() >= 0;
+    if (m_tree) m_tree->unselect();
+    if (m_parts) m_parts->unselect();
+    return any;
+}
+
 void DesignPanel::update_section_flip_btn()
 {
     if (m_section_flip_btn) m_section_flip_btn->Enable(m_section_on);
@@ -11763,11 +11779,12 @@ void DesignPanel::escape()
         }
         return;
 
-    case CadLevel::Idle:
+    case CadLevel::Idle: {
         // Deselect. In a sketch this is the floor: the session is left through Finish or Cancel,
         // both of which say which one they are, and never through a key pressed on the way out of
-        // something else.
-        if (m_viewport && m_viewport->clear_any_selection()) {
+        // something else. The Feature tree and Bodies rows count as selections too.
+        const bool row = deselect_rows();
+        if ((m_viewport && m_viewport->clear_any_selection()) || row) {
             set_status(StatusKind::Info, wxString());
             return;
         }
@@ -11783,6 +11800,7 @@ void DesignPanel::escape()
         }
         return;
     }
+    }
 }
 
 bool DesignPanel::menu_can_undo_redo(bool redo) const

src/slic3r/GUI/CAD/DesignPanel.hpp

@@ -916,6 +916,7 @@ private:
     bool     m_hl_pending{false};
     void     request_feature_highlight();
     void     update_feature_highlight();
+    bool     deselect_rows();       // Esc / a click on nothing: drop the tree and Bodies rows
     // Bodies list under the feature tree: one row per body (parallel to m_doc.bodies). Selecting
     // one highlights that body and makes it the target for the next op.
     DesignRowList*            m_parts{nullptr};

src/slic3r/GUI/CAD/DesignSketchTool.cpp

@@ -3813,6 +3813,7 @@ void DesignSketchTool::pick_bodies_in_rectangle()
     dp_pick_trace("rubber band -> body=%d (%d samples)", best, best_n);
     if (on_solid_selection_changed)
         on_solid_selection_changed(int(m_solid_sel), m_sel_body, m_sel_face, m_sel_edge);
+    if (best < 0 && on_empty_pick) on_empty_pick();
 }
 
 // Resolve what a pick at (mx,my) would take. CONST, and it writes only into `out`: the hover
@@ -10782,6 +10783,7 @@ bool DesignSketchTool::on_mouse_impl(wxMouseEvent& evt, GLCanvas3D& canvas)
                 return true;
             }
         }
+        if (on_empty_pick) on_empty_pick();
         return false;                                     // let the stock canvas orbit / deselect
     }
 

src/slic3r/GUI/CAD/DesignSketchTool.hpp

@@ -235,6 +235,9 @@ public:
     std::function<void(int body, const Transform3d& xform)> on_body_move_changed;
     // Fired on each cycle change: (level 0=None/1=Whole/2=Face/3=Edge, body index, face id, edge id).
     std::function<void(int level, int body, int face, int edge)> on_solid_selection_changed;
+    // A click or rubber band (no live session) that took nothing, so the host can drop the
+    // selections the tool does not hold, such as the panel's list rows.
+    std::function<void()> on_empty_pick;
     // Click a committed sketch overlay (no live session) -> select that loop: the Sketch
     // feature index + the clicked closed-region index within it (-1 = no specific loop).
     // entity = the sketch entity index under the cursor when the click landed on a loop