Reset device selection on agent swap or unload (#124)

set_live_printer_agent centralizes
the swap: deselect the machine,
clear stale sidebar state and the
previous agent's Other Devices, then
install the new agent (or null when
its provider vanished). Plugin
load/unload callbacks refresh the
dropdown and re-run agent selection.
load_last_machine no longer falls
back to the first available machine.

src/slic3r/GUI/DeviceCore/DevManager.cpp

@@ -496,6 +496,26 @@ namespace Slic3r
         OnSelectedMachineChanged(previous_selected_machine, selected_machine);
     }
 
+    void DeviceManager::clear_other_devices()
+    {
+        // why: on agent swap, keep "My Devices" but drop the transient "Other Devices"
+        // Those belong to the previous agent's network scan; the new agent's start_discovery re-populates its own.
+        const auto my = get_my_machine_list();
+        for (auto it = localMachineList.begin(); it != localMachineList.end();)
+        {
+            if (my.find(it->first) == my.end())
+            {
+                // not a "My Device" -> an "Other Device"
+                delete it->second;
+                it = localMachineList.erase(it);
+            }
+            else
+            {
+                ++it;
+            }
+        }
+    }
+
     bool DeviceManager::set_selected_machine(std::string dev_id)
     {
         BOOST_LOG_TRIVIAL(info) << "set_selected_machine=" << dev_id
@@ -558,7 +578,6 @@ namespace Slic3r
             }
             else
             {
-                Slic3r::GUI::wxGetApp().reset_unsigned_plugin_warning();
                 if (m_agent)
                 {
                     if (it->second->connection_type() != "lan" || it->second->connection_type().empty())
@@ -592,7 +611,6 @@ namespace Slic3r
         }
 
         selected_machine = dev_id;
-        record_user_last_machine(selected_machine);
         return true;
     }
 
@@ -857,40 +875,20 @@ namespace Slic3r
         }
     }
 
-    void DeviceManager::record_user_last_machine(const std::string& dev_id)
-    {
-        if (Slic3r::GUI::wxGetApp().app_config) {
-            Slic3r::GUI::wxGetApp().app_config->set("user_last_selected_machine", dev_id);
-        }
-    }
-
-    std::string DeviceManager::get_user_last_machine() const
-    {
-        if (Slic3r::GUI::wxGetApp().app_config) {
-            const auto& user_last_machine = Slic3r::GUI::wxGetApp().app_config->get("user_last_selected_machine");
-            if (!user_last_machine.empty()) {
-                return user_last_machine;
-            } else if (m_agent) {
-                return m_agent->get_user_selected_machine();
-            }
-        }
-
-        return "";
-    }
-
     void DeviceManager::load_last_machine()
     {
-        if (userMachineList.empty()) return;
-        else if (userMachineList.size() == 1) {
-            this->set_selected_machine(userMachineList.begin()->second->get_dev_id());
-        } else {
-            const auto& last_monitor_machine = get_user_last_machine();
-            if (userMachineList.find(last_monitor_machine) != userMachineList.end()) {
-                set_selected_machine(last_monitor_machine);
-            } else {
-                this->set_selected_machine(userMachineList.begin()->second->get_dev_id());
-            }
-        }
+        // Get all available machines, include cloud machines and lan machines that have access right
+        auto all_machines = get_my_machine_list();
+        if (all_machines.empty())
+            return;
+        
+        // Reconnect the machine the user last selected, if it's still available.
+        // why: no first-available fallback - auto-connecting an arbitrary machine
+        // fights the agent-swap reset, which intentionally leaves nothing selected.
+        const std::string last_monitor_machine = m_agent ? m_agent->get_user_selected_machine() : "";
+        const auto        last_machine = all_machines.find(last_monitor_machine);
+        if (last_machine != all_machines.end())
+            this->set_selected_machine(last_machine->second->get_dev_id());
     }
 
     void DeviceManager::OnMachineBindStateChanged(MachineObject* obj, const std::string& new_state)

src/slic3r/GUI/DeviceCore/DevManager.h

@@ -48,8 +48,9 @@ public:
     MachineObject* get_selected_machine();
     bool set_selected_machine(std::string dev_id);
 
-    void record_user_last_machine(const std::string& dev_id);
-    std::string get_user_last_machine() const;
+    // why: clears stale sidebar sync-status / AMS visuals. Public so the printer-agent
+    // swap path can reuse it instead of duplicating the two sidebar calls.
+    void OnSelectedMachineLost();
 
     // local machine
     void           set_local_selected_machine(std::string dev_id) { local_selected_machine = dev_id; };
@@ -70,6 +71,8 @@ public:
     void erase_user_machine(std::string dev_id) { userMachineList.erase(dev_id); }
     void clean_user_info(bool keep_local_selection = false);
 
+    void clear_other_devices();
+
     void load_last_machine();
     void update_user_machine_list_info(const std::string& provider);
     void parse_user_print_info(std::string body);
@@ -110,7 +113,6 @@ private:
     void check_pushing();
 
     void OnMachineBindStateChanged(MachineObject* obj, const std::string& new_state);
-    void OnSelectedMachineLost();
     void OnSelectedMachineChanged(const std::string& pre_dev_id, const std::string& new_dev_id);