It is found that tsplitter is not easy to use in nesting and simply writes a substitute

Tdirpanel class that replaces tsplitter:

Unit dirpanel; interfaceuses classes, controls, forms, extctrls; Type tdirpanel = Class (tcustompanel) Private fline: tpanel; B: Boolean; F: integer; protected procedure linemousedown (Sender: tobject; button: tmousebutton; shift: tshiftstate; X: integer; Y: integer); Procedure linemousemove (Sender: tobject; shift: tshiftstate; X: integer; Y: integer ); procedure linemouseup (Sender: tobject; button: tmousebutton; shift: tshiftstate; X: integer; Y: integer); Public constructor create (aowner: tcomponent; aalign: talign = alleft ); reintroduce; destructor destroy; override; published end; implementation {tdirpanel} constructor tdirpanel. create (aowner: tcomponent; aalign: talign); begin inherited create (aowner); fline: = tpanel. create (Self); fline. parent: = self; Case aalign of altop: Begin fline. align: = Albottom; fline. height: = 5; fline. cursor: = crvsplit; constraints. maxheight: = screen. height Div 4; constraints. minheight: = fline. height; end; alleft: Begin fline. align: = alright; fline. width: = 5; fline. cursor: = crheat transport; constraints. minwidth: = fline. width; constraints. maxwidth: = screen. width Div 2; end; align: = aalign; bevelouter: = bvnone; fline. onmousedown: = linemousedown; fline. onmousemove: = linemousemove; fline. onmouseup: = linemouseup; end; destructor tdirpanel. destroy; begin fline. free; inherited; end; Procedure tdirpanel. linemousedown (Sender: tobject; button: tmousebutton; shift: tshiftstate; X, Y: integer); begin B: = true; Case align of altop: F: = y; alleft: f: = x; end; Procedure tdirpanel. linemousemove (Sender: tobject; shift: tshiftstate; X, Y: integer); begin if not B then exit; Case align of altop: Height: = height + Y-F; alleft: width: = width + X-F; end; Procedure tdirpanel. linemouseup (Sender: tobject; button: tmousebutton; shift: tshiftstate; X, Y: integer); begin B: = false; end.

Call test:

 
Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls, extctrls, olectrls, shdocvw, dirpanel; Type tform1 = Class (tform) procedure formcreate (Sender: tobject); end; var form1: tform1; implementation {$ R *. DFM} var dir1, dir2: tdirpanel; body: tpanel; web: twebbrowser; memo: tmemo; Procedure tform1.formcreate (Sender: tobject); begin body: = tpanel. create (Self); body. parent: = self; body. align: = alclient; body. bevelouter: = bvnone; dir1: = tdirpanel. create (Self); dir2: = tdirpanel. create (self, altop); dir1.parent: = self; dir2.parent: = body; web: = twebbrowser. create (Self); tcontrol (Web ). parent: = dir1; web. align: = alclient; web. navigate ('HTTP: // del.cnblogs.com '); memo: = tmemo. create (Self); memo. parent: = dir2; memo. align: = alclient; memo. text: = 'memo'; end.