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Q216985: BUG: Scrollbars Not Seen if Objects Placed Past Some Coordinates

Article: Q216985
Product(s): Microsoft FoxPro
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbContainer kbCtrl kbvfp kbvfp600bug kbGrpDSFox
Last Modified: 20-JAN-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 6.0 
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SYMPTOMS
========

After placing objects on a form that has scrollbars, the objects will not be
seen and the scrollbars will disappear when the form is run. This happens when
the objects have been placed too far vertically or horizontally down or across
the form.

CAUSE
=====

Visual FoxPro 6.0's forms were designed to have scrollbars that only scroll
approximately twice the length or width of the computer's video resolution.
Placing any objects past this point will result in the scrollbars disappearing
from the form.

RESOLUTION
==========

Do not set the Top and Left properties of any objects past the formula described
in the MORE INFORMATION section below.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.


MORE INFORMATION
================

By design, objects should not be placed beyond the coordinates (video resolution
* 2 - object height or width) in a form.For example, if the video resolution is
800x600, then placing a command button's Top property to 1173 (600 * 2 - 27) on
a form with vertical scrollbars will allow the user to scroll down the form and
select that command button at run-time. If the command button's Top property is
set to 1174, then the scrollbars will disappear and the command button cannot be
accessed. This number is based on the vertical resolution being 600, and the
height of the command button being 27.

The same situation occurs if the command button is positioned on a form with
horizontal scrollbars. Setting the Left property of the command button to 1516
(800 * 2 - 84) would allow the user to scroll across the form and select the
command button. Any number higher than that will make the scrollbars disappear
on the form.

This can be a problem if the form is run on another computer with a lower
resolution setting. For example, if a form is created on a computer with
1024x768 resolution and then run on a computer with 800x600 resolution, the
scrollbars will not be visible at the lower resolution. To ensure that the
scrollbars are visible at all resolutions, any objects placed on the form would
have to be set to the above formula using 640x480 as the base for the video
resolution.

It is not by design that the scrollbars disappear if an object is placed past
these points: the scrollbars should stay active, but the user would not be able
to scroll to any object that has been placed past these coordinates.

Steps to Reproduce Behavior
---------------------------

1. Run the following code. It creates a form with vertical and horizontal
  scrollbars that will have a command button in the bottom-right corner when
  both scrollbars are scrolled all the way down and right:

       scr_horizontal=SYSMETRIC(1) * 2 - 84 && Add one to the width or height
       scr_vertical=SYSMETRIC(2) * 2 - 27   && and the scrollbars will disappear.
       ? scr_horizontal
       ? scr_vertical
       DO get_form with scr_horizontal, scr_vertical

       PROCEDURE get_form

       PARAMETERS but_width, but_height
       PUBLIC oform1
       oform1=NEWOBJECT("form1")
       oform1.Show
       RETURN

       ****************************************
       DEFINE CLASS form1 AS form
                Top = 0
                Left = 0
                Height = 241
                Width = 209
                ScrollBars = 3
                DoCreate = .T.
                Caption = "Form1"
                Name = "Form1"

                       ADD OBJECT command1 AS commandbutton WITH ;
                              Top = 0, ;
                              Left = 0, ;
                              Height = 27, ;
                              Width = 84, ;
                              Caption = "Command1", ;
                              Name = "Command1"

                         PROCEDURE Init
                               Thisform.Command1.Left = but_width
                               Thisform.Command1.Top = but_height
                        ENDPROC
       ENDDEFINE

2. Increase the values of either the scr_horizontal or scr_vertical variable by
  one (1) and note that the scrollbars disappear.

REFERENCES
==========

For additional information about Scrollbars on forms, please see the following
article in the Microsoft Knowledge Base:

Q193749 PRB: Setting Scrollbars > 0 Changes Height and Width Property

Additional query words:

======================================================================
Keywords          : kbContainer kbCtrl kbvfp kbvfp600bug kbGrpDSFox 
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Version           : WINDOWS:6.0
Issue type        : kbbug
Solution Type     : kbpending

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