add etcpmon keyboard navigation: Tab between Server/Port, Enter=Connect, Esc=Disconnect

tools/etcpmon/etcpmon_gui.c

@@ -972,6 +972,31 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM l
                 return 0;
             }
             break;
+        case WM_KEYDOWN:
+            if (app) {
+                switch (wParam) {
+                    case VK_TAB: {
+                        HWND hFocus = GetFocus();
+                        if (hFocus == app->hEditAddr) {
+                            SetFocus(app->hEditPort);
+                            int len = GetWindowTextLengthA(app->hEditPort);
+                            SendMessageA(app->hEditPort, EM_SETSEL, len, len);
+                        } else if (hFocus == app->hEditPort) {
+                            SetFocus(app->hEditAddr);
+                            int len = GetWindowTextLengthA(app->hEditAddr);
+                            SendMessageA(app->hEditAddr, EM_SETSEL, len, len);
+                        }
+                        return 0;
+                    }
+                    case VK_RETURN:
+                        if (!app->isConnected) OnConnect(app);
+                        return 0;
+                    case VK_ESCAPE:
+                        if (app->isConnected) OnDisconnect(app);
+                        return 0;
+                }
+            }
+            break;
             
         case WM_DESTROY:
             PostQuitMessage(0);