Pascal: Project raising External: SIGSEGV when interacting with Form - lazarus

Question

Let's say, there are 3 forms in a project (Form1, Form2, Form3). Form1 has a button on it with the OnClick event set to Form2.Show. This code executes perfectly, however if Form2's code tries to call Form3.Show, then the project raises an EXTERNAL: SIGSEGV pointing to Customform.inc
Project project1 raised exception class 'External: SIGSEGV'
In file '.\include\customform.inc' at line 2196:
Visible := True;
This is exactly what's happening to my project. All forms were properly created and declared, and the units are linked perfectly. The compilation goes fine, without any errors or warnings.
So it is impossible to make the third form visible. But I've discovered that every kind of interaction would result in an External: SIGSEGV error pointing to random pieces of code which compile and run just fine. I just can't figure out the origin of the error.
If I try to execute my project without the debugger, I get an Access Violation error. Failing code:
procedure TWarForm.FormCreate(Sender: TObject);
Begin
Form3.Show;
end;
from
unit work;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls,
StdCtrls, BGRAFlashProgressBar, AuthUnit;
type
{ TWarForm }
TWarForm = class(TForm)
ArcaneDustIMG: TImage;
ProgressBar: TBGRAFlashProgressBar;
ArcaneEDT: TEdit;
GoldEDT: TEdit;
GoldIMG: TImage;
Label1: TLabel;
Wallpaper: TImage;
procedure FormCreate(Sender: TObject);
procedure WallpaperMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure WallpaperMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
procedure WallpaperMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
private
{ private declarations }
public
{ public declarations }
end;
var
WarForm: TWarForm;
MouseIsDown: Boolean;
PX, PY: Integer;
implementation
{$R *.lfm}
{ TWarForm }
procedure TWarForm.WallpaperMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
if Button = mbLeft then begin
MouseIsDown := True;
PX := X;
PY := Y;
end;
end;
procedure TWarForm.FormCreate(Sender: TObject);
Begin
Form3.Show;
end;
procedure TWarForm.WallpaperMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if MouseIsDown then begin
SetBounds(WarForm.Left + (X - PX), WarForm.Top + (Y - PY), WarForm.Width, WarForm.Height);
end;
end;
procedure TWarForm.WallpaperMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
MouseIsDown:=False;
end;
end.

Answer 1

You have to create the forms either manualy or set them to "auto create" in your IDE
To Create them manualy just change your code slightly:
TWarForm = class(TForm)
ArcaneDustIMG: TImage;
ProgressBar: TBGRAFlashProgressBar;
ArcaneEDT: TEdit;
GoldEDT: TEdit;
GoldIMG: TImage;
Label1: TLabel;
Wallpaper: TImage;
Form2: TForm2; // insert Form2
Form3: TForm3; // and Form3
procedure FormCreate(Sender: TObject);
procedure WallpaperMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure WallpaperMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
procedure WallpaperMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
private
{ private declarations }
public
{ public declarations }
end;
..
procedure TWarForm.FormCreate(Sender: TObject);
Begin
Form3 := TForm3.Create(Self);
Form3.Show;
end;
If you do so, don't forget to call Form3.Free at the end of your application execution.