rapps: various small fixes

The patch fixes those issues:

1. richedit control being hidden when minimizing then restoring application window;
2. graphical richedit glitch when application window height is reduced;
3. save/load vertical/horizontal splitter size, listview column length;
4. window being restored to max size after clicking 'restore' if maximized window was closed previously.

Patch by Edijs Kolesnikovičs and Grégori Macário Harbs.