# Drag and drop in custom application does not work
**URL:** https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172
**Category:** Development
**Created:** [September 9, 2025, 12:19pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172 "2025-09-09T12:19:08Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@CsatiZoltan](https://discourse.paraview.org/u/CsatiZoltan)
#### Post date: [September 9, 2025, 12:19pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/1 "2025-09-09T12:19:08Z")
Hi,
I built ParaView from the master branch, then used this ParaView to build the _SimpleParaView_ example application. Drag & drop a file to the render window works in ParaView that I built, but not in the custom application. Was drag & drop deactivated on purpose in the _SimpleParaViewI_?
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [September 9, 2025, 3:06pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/2 "2025-09-09T15:06:00Z")
In `ParaView/ParaViewMainWindow.cxx ` there is this code:
```auto
//-----------------------------------------------------------------------------
void ParaViewMainWindow::dragEnterEvent(QDragEnterEvent* evt)
{
pqApplicationCore::instance()->getMainWindowEventManager()->dragEnterEvent(evt);
}
//-----------------------------------------------------------------------------
void ParaViewMainWindow::dropEvent(QDropEvent* evt)
{
pqApplicationCore::instance()->getMainWindowEventManager()->dropEvent(evt);
}
```
And also the following in `ParaView/ParaViewMainWindow.ui`
```auto
true
```
Which is not present in SimpleParaView
---
### Author:  [@CsatiZoltan](https://discourse.paraview.org/u/CsatiZoltan)
#### Post date: [September 9, 2025, 3:39pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/3 "2025-09-09T15:39:39Z")
Thank you. Does it need modification in the build system? Adding these (along with the declarations in the header file) was not enough:
```bash
/home/zc/paraview/Examples/CustomApplications/SimpleParaView/client/myMainWindow.cxx: In member function ‘virtual void myMainWindow::dragEnterEvent(QDragEnterEvent*)’:
/home/zc/paraview/Examples/CustomApplications/SimpleParaView/client/myMainWindow.cxx:88:61: error: invalid use of incomplete type ‘class pqMainWindowEventManager’
88 | pqApplicationCore::instance()->getMainWindowEventManager()->dragEnterEvent(evt);
| ^~
In file included from /home/zc/paraview/Examples/CustomApplications/SimpleParaView/client/myMainWindow.cxx:7:
/home/zc/paraview_install/include/paraview-6.0/pqApplicationCore.h:17:7: note: forward declaration of ‘class pqMainWindowEventManager’
17 | class pqMainWindowEventManager;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~
/home/zc/paraview/Examples/CustomApplications/SimpleParaView/client/myMainWindow.cxx: In member function ‘virtual void myMainWindow::dropEvent(QDropEvent*)’:
/home/zc/paraview/Examples/CustomApplications/SimpleParaView/client/myMainWindow.cxx:94:61: error: invalid use of incomplete type ‘class pqMainWindowEventManager’
94 | pqApplicationCore::instance()->getMainWindowEventManager()->dropEvent(evt);
| ^~
/home/zc/paraview_install/include/paraview-6.0/pqApplicationCore.h:17:7: note: forward declaration of ‘class pqMainWindowEventManager’
17 | class pqMainWindowEventManager;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~
```
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [September 9, 2025, 3:40pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/4 "2025-09-09T15:40:31Z")
Probably an include ?
---
### Author:  [@CsatiZoltan](https://discourse.paraview.org/u/CsatiZoltan)
#### Post date: [September 9, 2025, 3:46pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/5 "2025-09-09T15:46:41Z")
I included
```cpp
#include
#include
```
so it shouldn’t be the problem. By the way, _Clients/ParaView/ParaViewMainWindow.cxx_ only includes `QDragEnterEvent`, so `QDropEvent` must be included implicitly.
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [September 9, 2025, 3:47pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/6 "2025-09-09T15:47:35Z")
> [@CsatiZoltan](#):
>
> `pqMainWindowEventManager`
`#include "pqMainWindowEventManager.h"`
---
### Author:  [@CsatiZoltan](https://discourse.paraview.org/u/CsatiZoltan)
#### Post date: [September 9, 2025, 3:57pm UTC](https://discourse.paraview.org/t/drag-and-drop-in-custom-application-does-not-work/17172/7 "2025-09-09T15:57:19Z")
Sorry, my bad. It works now.