You can change that by going to tools options and windows and checkmark Use single button
in taskbar.
also after your changes and you restart lazarous you can adjust windows, ie code explorer, object properties
etc, and save and next time you open lazarus they will all be where you left them.
Use Ctl + F12 to show your form if you have multiple forms, then select the form from the list
you need to alter.
For just one form use F12
hope this helps