feature add tips for import failed.

src/slic3r/GUI/DownloadManager.cpp

@@ -1,5 +1,6 @@
 #include "DownloadManager.hpp"
 #include "GUI_App.hpp"
+#include "libslic3r/Utils.hpp"
 #include <boost/filesystem.hpp>
 #include <boost/nowide/fstream.hpp>
 #include <boost/log/trivial.hpp>
@@ -257,6 +258,8 @@ void DownloadManager::start_download_impl(std::shared_ptr<DownloadTask> task) {
                         if (!file.is_open()) {
                             std::string error_msg = "Failed to open file for writing: " + task->dest_path;
                             BOOST_LOG_TRIVIAL(error) << "DownloadManager: " << error_msg;
+                            // Flush logs immediately for critical errors
+                            Slic3r::flush_logs();
                             send_error_update(task, error_msg);
                             cleanup_task(task->task_id);
                             return;
@@ -266,6 +269,8 @@ void DownloadManager::start_download_impl(std::shared_ptr<DownloadTask> task) {
                         if (file.fail()) {
                             std::string error_msg = "Failed to write file: " + task->dest_path;
                             BOOST_LOG_TRIVIAL(error) << "DownloadManager: " << error_msg << ", body size: " << body.size();
+                            // Flush logs immediately for critical errors
+                            Slic3r::flush_logs();
                             file.close();
                             send_error_update(task, error_msg);
                             cleanup_task(task->task_id);
@@ -280,6 +285,8 @@ void DownloadManager::start_download_impl(std::shared_ptr<DownloadTask> task) {
                     } catch (std::exception& e) {
                         std::string error_msg = std::string("File write exception: ") + e.what();
                         BOOST_LOG_TRIVIAL(error) << "DownloadManager: " << error_msg << ", file: " << task->dest_path;
+                        // Flush logs immediately for critical errors
+                        Slic3r::flush_logs();
                         send_error_update(task, error_msg);
                         cleanup_task(task->task_id);
                     }
@@ -301,6 +308,8 @@ void DownloadManager::start_download_impl(std::shared_ptr<DownloadTask> task) {
                         << ", URL: " << task->file_url 
                         << ", file: " << task->file_name
                         << ", dest: " << task->dest_path;
+                    // Flush logs immediately for critical errors to ensure they are written
+                    Slic3r::flush_logs();
                     task->state = DownloadTaskState::Error;
                     task->error_message = error;
                     send_error_update(task, error);

src/slic3r/GUI/GenericDownloadDialog.cpp

@@ -355,6 +355,7 @@ void GenericDownloadDialog::on_download_error(size_t task_id, const std::string&
 
 void GenericDownloadDialog::on_retry_clicked(wxCommandEvent& event)
 {
+    SetTitle(m_title);
     if (m_on_retry) {
         m_on_retry();
     }
@@ -399,6 +400,8 @@ void GenericDownloadDialog::show_error_page(const std::string& error_msg)
 {
     m_simplebook_status->SetSelection(2);
 
+    SetTitle(_L("Donwload failed"));
+
     // Display simple error message: filename + "Download failed"
     wxString filename = wxString::FromUTF8(m_file_name.c_str());
     wxString error_text = filename + " - Download failed";

src/slic3r/GUI/MainFrame.cpp

@@ -4038,6 +4038,12 @@ void MainFrame::downloadOpenProject(const std::string& fileUrl, const std::strin
             wxGetApp().mainframe->plater()->load_project(wx_file_path);
         }
     }
+    else
+    {
+        // Not a valid 3mf file, show error message
+        wxString msg = wxString::Format(_L("The downloaded file '%s' is not a valid 3MF project file."), fileName);
+        MessageDialog(this, msg, _L("Invalid File"), wxOK | wxICON_WARNING).ShowModal();
+    }
 
 
 }