[Lazarus] QCoreApplication::postEvent: Unexpected null receiver

[FreeMan]

error create after form destroy, so many times I check All class & 
components is free. "TFRM_.FormDestroy( >3" this is debugln command last 
code on onformdestroy.
Access violation  some time create and stop "QCoreApplication....." 
message and application continue
I couldn't find this error as long as two days. I found on the internet, 
error is object is deleting so post event return null, can be but which 
one ? how can I find it?
has any suggestion ?
Thank you.


➜  apps  ./_linux
Bus::open: Can not get ibus-daemon's address.
IBusInputContext::createInputContext: no connection to ibus-daemon
QPainter::begin: Paint device returned engine == 0, type: 2
QPainter::end: Painter not active, aborted
[HINT] TWinControl.CreateWnd creating Handle during loading 
PGC_Hekims:TTabControl csDesigning=False
TFRM_.FormClose( >1
TFRM_.FormClose( >2
TFRM_.FormClose( >3
TFRM_.FormClose( >4
TFRM_.FormDestroy( >1
TFRM_.FormDestroy( >2
TFRM_.FormDestroy( >3
QCoreApplication::postEvent: Unexpected null receiver
QCoreApplication::postEvent: Unexpected null receiver
QCoreApplication::postEvent: Unexpected null receiver
QCoreApplication::postEvent: Unexpected null receiver
QCoreApplication::postEvent: Unexpected null receiver
TApplication.HandleException Access violation
   Stack trace:
   $00007FCB2D1EC11D
   $00000000005B9708
   $00000000005B6C5A
   $00000000006E1BA7
   $00007FCB2D1FC87A