screens sometimes skip when using down arrow

[Matthew Sprague]

Windows Vista Home Premium
OpenLP 1.9.8

Last Sunday 3/11/2012 we were running the slides and they kept skipping past the desired slide. I thought the guy running them was just impatient and hitting the arrow too many times. I was setting up the service for next week and running through the slides and then it happened to me.

The steps to reproduce are:
open the song
down arrow through the slides
use the up arrow to go back to the top
down arrow slowly down
wait for the skip.

if you use the mouse to jump around, then it seems to get back on track

It is crazy, but if you make a mistake or the song leader gets a blast of the holy spirit, it can drive the technician nuts.

[Jonathan Corwin (j-corwin)]

I didn't see it with a single colour background, but then I changed to a theme with an image background and a 5 verse song.
I cursored down. I then kept my finger on the up arrow to get to the top quickly and released the key.
After a short moment the slide suddenly jumped back to verse 3 by itself.

[Jonathan Corwin (j-corwin)]

My Service Item Slide Limits setting is "End slide"

[Jonathan Stafford (staffj01)]

I haven't had time to try this myself, but to me, this sounds rather similar to Bug #892571 (Service Manager Keys do mad things).

That problem was showing up moving quickly between Service Items using the left/right arrow keys. Tim ended up implementing a queue to store keypresses and then execute them one at a time.

[Stevan Pettit (elderp-deactivatedaccount)]

Using OpenLP 1.9.12 build bzr2070
Windows 7

I picked a theme with an image background and large font. Made this the default theme.

When displaying a song, only one line fits on the screen.
Set Service Item Slide Limits -> Wrap around.

Pressed and held the down arrow key.

Slides display and loop for about 2 1/2 iterations, then the following windows error occurs.

Problem signature:
  Problem Event Name: APPCRASH
  Application Name: OpenLP.exe
  Application Version: 0.0.0.0
  Application Timestamp: 4fbf5043
  Fault Module Name: QtGui4.dll
  Fault Module Version: 4.7.3.0
  Fault Module Timestamp: 4dd01967
  Exception Code: c00000fd
  Exception Offset: 004dc1b7
  OS Version: 6.1.7601.2.1.0.256.48
  Locale ID: 1033
  Additional Information 1: d483
  Additional Information 2: d4835b36caef45e352cd5171da54a30c
  Additional Information 3: f35f
  Additional Information 4: f35f9d99316109b9601d14f93b57e2e2

I've had this problem before when coding Visual Basic programs. I fixed that problem by flushing the keyboard buffer just before exiting the routine that processes the keyboard function.

If the user is holding the key down, the function get called again immediately and they (the user) sees what is expected.

If i set wrap off, I see the behavior of the selection "jumping". Flushing the buffer should take care of this also.

I can duplicate this problem easily.

[Phill (phill-ridout)]

I can confirm this on windows 7 too using the latest version of trunk.
I was investigating another bug and previewed a long bible passage.
Default theme (black background, basic text)
Pressing the down arrow in quick succession (but not unreasonably so), caused it to change down, but after it had finished going down it would jump back up several verses.

[Raoul Snyman (raoul-snyman)]

This is because the selection index in the table widget and the actual slide behind the scenes get out of sync. A simple solution would be to set the selection index when the keypress queue is empty.

[Tomas Groth (tomasgroth)]

This is still an issue. I'll try to make a fix after beta2 is out.