Upon minimizing application's window, all modified data will be stored and program (depending on settings) will be visible either as a small icon near system clock (so called "tray icon"), or as a button on a taskbar. Clicking tray icon with a right mouse button will bring a tray icon context menu. To restore application, use the first command or double-click the tray icon.
Among standard commands, at the very end there's "Free some memory" command - use it to unload all unused additional libraries (PCRE, graphics support library, Winsock, etc), unload unused folders and free unused message editors. This way you can quickly reduce resource and memory usage. Note that freed libraries and unloaded folders may need to be reloaded before another use.