FIX: TopMost Window Does Not Stay on Top in Design Environment

The SetWindowPos API function can be used to set a window so that it stays on the top of all other windows. However, the window will not stay on top in the Visual Basic design environment.

There is no workaround to keep a window TopMost while in the Design Environment. However, when the application is compiled to an EXE, invoking the SetWindowPos function to keep a Visual Basic form TopMost will correctly work.

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

In the Design environment, making a form TopMost causes it to stay on top of other Visual Basic Design Environment windows, such as the Properties window and Debug window until another application is switched to. Once another application has been made active, the form in Visual Basic loses its TopMost attribute, and when the focus returns to Visual Basic, it even stays behind the other windows within Visual Basic.

To see how the SetWindowPos API function can be applied to keep a window TopMost, please see the CallDLLs sample located in the vb\samples\calldlls directory. The declaration for the function is in the Declares.bas file, and the call to SetWindowPos is located in the mnuSysInfo_Click event contained in the frmMenus form.

Steps To Reproduce

1. In Visual Basic, open the vb\samples\CallDLLs sample.
2. Press F5 to run the project. Click on the picture of the computer with the right mouse button, and then select the "Always on Top" menu item from the pop-up menu. Now notice that other Visual Basic windows cannot be dragged over the CallDLLs form. Now switch to another application by pressing ALT+TAB. Notice that the other application can cover up the CallDLLs window. Now switch back to Visual Basic, and notice that now the other Visual Basic Design environment windows can cover up the CallDLLs form.

To correct this behavior, the sample can be compiled as an EXE, and then after selecting the Always on Top menu item, the window will correctly stay on top of other windows.