[Lazarus] strange bug in source editor, disappearing scroll bar

Martin lazarus at mfriebe.de
Thu Nov 4 12:16:15 CET 2010

On 04/11/2010 01:44, Bernd Kreuss wrote:
> please compare these two screen shots:
> http://imagebin.org/121695
> http://imagebin.org/121699
> Pay attention to the scrollbar and the sunken border around the edit
> area. All I did was pressing enter on this line. If I remove the line
> break again it will reappear, as often as I want. It does not happen
> when I move it to a new edit window. It will happen again if I restart
> lazarus. It happens only on windows.
There seem to issues.

* If scrollbars a present, then synedit for some reason alos draws a 
border around the client area( just 1 or pixel).

* But the bigger issue is the missing repaint of the area where the 
scrollbar should be.
This seems a new issue.
  I noticed it a similar thing myself on single time, and couldn't 
reproduce it yet.

In my case I had a small area at the bottom of the synedit, that was not 
repainted. (the area where a hoirzental scrollbar could have been). \in 
my case it was not expected to be there. (but may have been there before).
In my case the error disapeared, by resizing the window.
My suspicion in my case is that the client area was not updated by the 
lcl, and synedit could not know it had to draw there.

if it is a missing update of the client area, then it is lcl, and may 
affect other components too.?

I cant do anything at present as I am away over the week.

I recommend to put some debugln code into :
1) \SynEdit.UpdateScrollbars .
at least to output some log msg when synedit actually sets the visibilty 
of the scrollbar => so we know if synedit did hide them, or the lcl

2) also put debugln into the resize mesage handler, in synedit. so you 
know if a resize msg was received. including the size of the clientrect


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