Here is an explanation of all the relevant parameters: http://www.cnblogs.com/del/archive/2008/04/15/1154359.html
// Maximize the window procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. style: = Params. style or ws_maximize; {ws_minimize is minimized} end; // cancel the system menu (if you cannot close it, use Alt + F4) Procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; params. style: = Params. style and not ws_sysmenu; end; // deselect the border procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. style: = Params. style and not ws_thickframe; end; // procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. exstyle: = Params. exstyle or ws_ex_topmost; end; // tool window procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. exstyle: = Params. exstyle or ws_ex_toolwindow; end; // visual procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. exstyle: = Params. exstyle or ws_ex_clientedge; end; // procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. style: = Params. style and not (ws_minimizebox or ws_maximizebox); Params. exstyle: = Params. exstyle or ws_ex_contexthelp; end; // hide the title bar procedure tform1.createparams (VAR Params: tcreateparams); begin inherited; Params. style: = ws_dlgframe or ws_popup; end;