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  1. Qt
  2. QTBUG-96234

QDrag::exec() produces thousands of error message "combase.dll: Class not registered"

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2: Important
    • Resolution: Out of scope
    • Affects Version/s: 5.12.11, 5.15
    • Fix Version/s: None
    • Environment:
      Dell P2418HT, VS 2017 and VS 2019, Windows SDK 10.0.19041.0 and 10.0.18362.0
      Dell - Latitude 5480
      Dell - Latitude 5500
      Dell Precision 5820 Tower
    • Platform/s:
      Windows

      Description

      Calling QDrag::exec() gives hundreds and even thousands of the following message, even during a short drag & drop operation:

      onecore\com\combase\dcomrem\resolver.cxx(2299)\combase.dll!00007FFDCC90206D: (caller: 00007FFDCC904F4E) ReturnHr(1) tid(3b3c) 80040154 Class not registered
      

      QDrag object's modal loop gets so busy (probably waiting for the messages to be written out) that it becomes sluggish and appears hung.
      Also, the drop event often gets lost when the messages are being written, causing the object to get stuck waiting for the dragging to end.
      All the while, the same message continues to get written out.

      Similar discussion is in https://forum.qt.io/topic/123927/qdrag-qdropevent-combase-error-class-not-registered/2

      How to reproduce
      Use https://doc.qt.io/qt-5/qtwidgets-itemviews-puzzle-example.html
      and try dragging

      Known issue

      • Happen with touch panel device
      • Both mouse dragging and tap dragging produce the same problem.

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              Assignee:
              owolff Oliver Wolff
              Reporter:
              nagrohn Nahomi Gröhn
              Votes:
              2 Vote for this issue
              Watchers:
              6 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:

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