with:

QT_LOGGING_RULES=qt.qpa.input.methods.debug=true

"5.8.1 windows" ()

#0 QLineEdit QInputMethodQueryEvent(queries=0x101, {})
#1 QLineEdit QInputMethodQueryEvent(queries=0x101, {})
qt.qpa.input.methods: QWindowsInputContext::startComposition QLineEdit(0x1679a3b5bc0) QWidgetWindow(0x1679a4432c0, name="QMainWindowClassWindow") language= 1042
#2 QLineEdit QInputMethodQueryEvent(queries=0x2, {})
qt.qpa.input.methods: QWindowsInputContext::cursorRectChanged QRect(7,53 10x14)
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "COMPSTR COMPATTR INSERTCHAR NOMOVECARET "  composing= true
#3 QLineEdit QInputMethodEvent(preedit="U+314e", attributes= {[type= 0, start=0, length=1, value=QVariant(QTextFormat, QTextFormat(QTextFormat::FormatType(2)))],[type= 1, start=0, length=0, value=QVariant(Invalid)]})
#4 QLineEdit QInputMethodQueryEvent(queries=0x1, {})
#5 QLineEdit QInputMethodQueryEvent(queries=0x2, {})
qt.qpa.input.methods: QWindowsInputContext::cursorRectChanged QRect(7,53 10x16)
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 2  commit= ""  to  QLineEdit(0x1679a3b5bc0)  returns  true
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "COMPSTR COMPATTR INSERTCHAR NOMOVECARET "  composing= true
#6 QLineEdit QInputMethodEvent(preedit="U+d558", attributes= {[type= 0, start=0, length=1, value=QVariant(QTextFormat, QTextFormat(QTextFormat::FormatType(2)))],[type= 1, start=0, length=0, value=QVariant(Invalid)]})
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 2  commit= ""  to  QLineEdit(0x1679a3b5bc0)  returns  true
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "COMPSTR COMPATTR INSERTCHAR NOMOVECARET "  composing= true
#7 QLineEdit QInputMethodEvent(preedit="U+d55c", attributes= {[type= 0, start=0, length=1, value=QVariant(QTextFormat, QTextFormat(QTextFormat::FormatType(2)))],[type= 1, start=0, length=0, value=QVariant(Invalid)]})
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 2  commit= ""  to  QLineEdit(0x1679a3b5bc0)  returns  true
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "RESULTSTR "  composing= true
#8 QLineEdit QInputMethodEvent(, commit="U+d55c")
#9 QLineEdit QInputMethodQueryEvent(queries=0x1, {})
#10 QLineEdit QInputMethodQueryEvent(queries=0x2, {})
qt.qpa.input.methods: QWindowsInputContext::cursorRectChanged QRect(18,53 10x16)
#11 QLineEdit QInputMethodQueryEvent(queries=0x1, {})
#12 QLineEdit QInputMethodQueryEvent(queries=0x2, {})
qt.qpa.input.methods: QWindowsInputContext::cursorRectChanged QRect(18,53 10x16)
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 0  commit= "?"  to  QLineEdit(0x1679a3b5bc0)  returns  true
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "COMPSTR COMPATTR INSERTCHAR NOMOVECARET "  composing= false
#13 QLineEdit QInputMethodQueryEvent(queries=0x2, {})
qt.qpa.input.methods: QWindowsInputContext::cursorRectChanged QRect(18,53 10x16)
#14 QLineEdit QInputMethodEvent(preedit="U+3131", attributes= {[type= 0, start=0, length=1, value=QVariant(QTextFormat, QTextFormat(QTextFormat::FormatType(2)))],[type= 1, start=0, length=0, value=QVariant(Invalid)]})
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 2  commit= ""  to  QLineEdit(0x1679a3b5bc0)  returns  true
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "COMPSTR COMPATTR INSERTCHAR NOMOVECARET "  composing= true
#15 QLineEdit QInputMethodEvent(preedit="U+adf8", attributes= {[type= 0, start=0, length=1, value=QVariant(QTextFormat, QTextFormat(QTextFormat::FormatType(2)))],[type= 1, start=0, length=0, value=QVariant(Invalid)]})
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 2  commit= ""  to  QLineEdit(0x1679a3b5bc0)  returns  true
qt.qpa.input.methods: > QWindowsInputContext::composition QLineEdit(0x1679a3b5bc0) "COMPSTR COMPATTR INSERTCHAR NOMOVECARET "  composing= true
#16 QLineEdit QInputMethodEvent(preedit="U+ae00", attributes= {[type= 0, start=0, length=1, value=QVariant(QTextFormat, QTextFormat(QTextFormat::FormatType(2)))],[type= 1, start=0, length=0, value=QVariant(Invalid)]})
qt.qpa.input.methods: < QWindowsInputContext::composition sending markup= 2  commit= ""  to  QLineEdit(0x1679a3b5bc0)  returns  true
#17 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#18 QLineEdit QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#19 QWidget QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#20 QMainWindow QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#21 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyPress, Key_Control, ControlModifier)
#22 QLineEdit QKeyEvent(KeyPress, Key_Control, ControlModifier)
#23 QWidget QKeyEvent(KeyPress, Key_Control, ControlModifier)
#24 QMainWindow QKeyEvent(KeyPress, Key_Control, ControlModifier)

>>> ------------------- WM_IME_ENDCOMPOSITION is sent as soon as CTRL is pressed before commit() is even called

qt.qpa.input.methods: QWindowsInputContext::endComposition false 0x14a04c0
#25 QLineEdit QInputMethodEvent()
qt.qpa.input.methods: > QWindowsInputContext::composition QObject(0x0) "RESULTSTR "  composing= false
#26 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(ShortcutOverride, 0, ControlModifier, text="?")
#27 QLineEdit QKeyEvent(ShortcutOverride, 0, ControlModifier, text="?")
#28 QWidget QKeyEvent(ShortcutOverride, 0, ControlModifier, text="?")
#29 QMainWindow QKeyEvent(ShortcutOverride, 0, ControlModifier, text="?")
#30 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyPress, 0, ControlModifier, text="?")
#31 QLineEdit QKeyEvent(KeyPress, 0, ControlModifier, text="?")
#32 QWidget QKeyEvent(KeyPress, 0, ControlModifier, text="?")
#33 QMainWindow QKeyEvent(KeyPress, 0, ControlModifier, text="?")
#34 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyRelease, 0, ControlModifier, text="?")
#35 QLineEdit QKeyEvent(KeyRelease, 0, ControlModifier, text="?")
#36 QWidget QKeyEvent(KeyRelease, 0, ControlModifier, text="?")
#37 QMainWindow QKeyEvent(KeyRelease, 0, ControlModifier, text="?")
#38 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(ShortcutOverride, Key_A, ControlModifier, text="\u0001")
#39 QLineEdit QKeyEvent(ShortcutOverride, Key_A, ControlModifier, text="\u0001")
#40 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyPress, Key_A, ControlModifier, text="\u0001")
#41 QLineEdit QKeyEvent(KeyPress, Key_A, ControlModifier, text="\u0001")
#42 QLineEdit QInputMethodQueryEvent(queries=0x1, {})
#43 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyRelease, Key_A, ControlModifier, text="\u0001")
#44 QLineEdit QKeyEvent(KeyRelease, Key_A, ControlModifier, text="\u0001")
#45 QWidget QKeyEvent(KeyRelease, Key_A, ControlModifier, text="\u0001")
#46 QMainWindow QKeyEvent(KeyRelease, Key_A, ControlModifier, text="\u0001")
#47 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyRelease, Key_Control)
#48 QLineEdit QKeyEvent(KeyRelease, Key_Control)
#49 QWidget QKeyEvent(KeyRelease, Key_Control)
#50 QMainWindow QKeyEvent(KeyRelease, Key_Control)
#51 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#52 QLineEdit QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#53 QWidget QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#54 QMainWindow QKeyEvent(ShortcutOverride, Key_Control, ControlModifier)
#55 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyPress, Key_Control, ControlModifier)
#56 QLineEdit QKeyEvent(KeyPress, Key_Control, ControlModifier)
#57 QWidget QKeyEvent(KeyPress, Key_Control, ControlModifier)
#58 QMainWindow QKeyEvent(KeyPress, Key_Control, ControlModifier)
#59 QWidgetWindow/"QMainWindowClassWindow" QKeyEvent(KeyRelease, Key_Control)
#60 QLineEdit QKeyEvent(KeyRelease, Key_Control)
#61 QWidget QKeyEvent(KeyRelease, Key_Control)
#62 QMainWindow QKeyEvent(KeyRelease, Key_Control)