Qt Application looks different after being installed in Windows

[pixaeiro]

Hello,

I'm developing an application for Windows that uses Qt 5.10 and is compiled with Visual Studio 2015, and I'm using NSIS to pack and build the installer.

When I run the application that I have installed to the "c:\Program Files" directory it looks different than the application that I run from the build directory.

This is how it looks when I run it from the build directory:

p5Uqqdq.png

And this is how it looks when I run it from the "c:\Program Files" directory after it has been installed:

tBHaeyN.png

As you can see, the installed instance has something like a Windows XP look, with 3D buttons and frames.

Does anybody know what could be happening? Or has a hint of what to look for?

Thank you in advance for your help!

[d_stranz]

It looks like the default style used in your build environment is different from that used in your installed runtime environment. Does it look different in your build environment when you run Debug vs. Release mode builds?

You can also look at your Output window in Visual Studio when you run in debug mode. It will show a list of all of the DLLs loaded. In my system, it shows this for the style plugin:

'MyApp.exe' (Win32): Loaded 'C:\Qt\5_11_1\5.11.1\msvc2015_64\plugins\styles\qw indowsvistastyled.dll'

I am not sure how you can determine which style plugin is being loaded when you are running your installed app. Maybe you can retrieve the QStyle instance for qApp, then query the static QMetaObject for its className()?