[lazarus] One more cool little bug

Tony Maro tonym at nlisc.com
Tue Oct 8 14:46:36 EDT 2002

On Tue, 2002-10-08 at 12:31, Mattias Gaertner wrote:

> > When I try to create all my controls in the OnCreate event of my form,
> > half of them won't display, half display wrong, and the runtime
> > generated menus are completely scrambled with huge spaces between
> > entries and the order all wrong.  The same code placed in the OnShow
> > event of the same form works just fine.
> Plz don't send me an example or else the cool little bug will die.

Hadn't planned on it <<BG>>.

Seriously though, if you WANT the source I've posted it.  I'm not sure
if it happens every time or not but I've definitely seen it.  That's why
I was kind of wondering if anybody else had seen that happen...  It
didn't do this on mine until I was creating a lot of components at


Look in the oncreate and onshow events of the FrmMain (unitmain.pas).  I
commented out code from it's usual location in the onshow event and
pasted it into the end of the oncreate event.  Even though it probably
SHOULD work the net result is quite complex...

If you compile and run this as is, it will crash with tons of errors
about invalid parents and the like.  I just realized that.  

If however you put the code back to normal, run it once, create a new
checkbook file and exit (so it will auto-load it next time) THEN you run
the above posted code, it will run (throwing tons of GTK warnings) and
scrambles things.

Simply moving the same code from OnCreate to OnShow fixes the issue.  


After painful testing I found that changing the order and creating the
menus BEFORE the LblAboutTransactions component while in the OnCreate
event also seems to fix it.  If I create the menus AFTER I create that
label, the menus are trashed and throw GTK errors everywhere, UNLESS
it's done in the OnShow event.

Go figure.

Like I said, it's pretty complex and I'm not positive there's not some
aspect of my code interfering, but I don't think so.

I've seen almost identical problems with placing all the controls on the
form at design time - that's why I switched to creating at runtime.


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