On an XFA enabled build:

1. Open https://www.canada.ca/content/dam/ircc/migration/ircc/english/pdf/kits/forms/imm5257e.pdf
2. Open the dropdown under "5. Place of birth" "* Country".
3. Click the up scrollbar arrow in the popup.
4. Click the dragging bar in the popup.

Expected: Nothing

Actual: Crash with stack:

Received signal 11 <unknown> 000000000000
#0 0x7feb0c6b46ad base::debug::StackTrace::StackTrace()
#1 0x7feb0c6b2b9c base::debug::StackTrace::StackTrace()
#2 0x7feb0c6b4075 base::debug::(anonymous namespace)::StackDumpSignalHandler()
#3 0x7feb0cc170c0 <unknown>
#4 0x561cd8cca943 CFWL_TimerInfo::StopTimer()
#5 0x561cd8ddaa80 CFWL_ScrollBar::OnLButtonUp()
#6 0x561cd8dda7c5 CFWL_ScrollBar::OnProcessMessage()
#7 0x561cd8ce1b12 CFWL_NoteDriver::DispatchMessage()
#8 0x561cd8ce1833 CFWL_NoteDriver::ProcessMessage()
#9 0x561cd8ce9160 CFWL_WidgetMgr::OnProcessMessageToForm()
#10 0x561cd8ddd210 CXFA_FFField::TranslateFWLMessage()
#11 0x561cd8ddd6d2 CXFA_FFField::OnLButtonUp()
#12 0x561cd8efa1ea CXFA_FFWidgetHandler::OnLButtonUp()
#13 0x561cd87aaad1 CPDFSDK_XFAWidgetHandler::OnLButtonUp()
#14 0x561cd877a0a5 CPDFSDK_AnnotHandlerMgr::Annot_OnLButtonUp()
#15 0x561cd8771100 CPDFSDK_PageView::OnLButtonUp()
#16 0x561cd876ba58 FORM_OnLButtonUp
#17 0x561cd86fe25e chrome_pdf::PDFiumEngine::OnMouseUp()
#18 0x561cd86fd712 chrome_pdf::PDFiumEngine::HandleEvent()
#19 0x561cd86d164a chrome_pdf::OutOfProcessInstance::HandleInputEvent()