Getting along with qwt on Qt

Smooth experience with Qwt on Windows with Visual Studio.

1. Build qwt on Windows: https://www.qtcentre.org/threads/66576-Installing-Qwt-with-MSVC-2015-64bit-compiler-on-Windows-(complete-instructions) — that works on VS-2019 as well.
2. You will need QtDesigner with VS. Install a plugin: copy from qwt-6.1.4\plugins\designer\ to qt\5.13.1\msvc2017_64\plugins\designer\. Run qt\5.13.1\msvc2017_64\bin\designer.exe and see this at Help → About Plugins:
   
3. You also need a plugin at QtCreator. It is a 32-bit app :( So you compile qwt for 32-bit, keep it fully separately from 64-bit one (i.e. unzip your qwt downloadable to a separate folder again, name it qwt-x86-6.1.4). Copy qwt-x86-6.1.4/plugins/designer/qwt_designer_plugin.dll to qt/Tools/QtCreator/bin/plugins/designer. Create a Widget application, go to a form and find this in the panel:
   
4. Create a VS Qt project, then export a QtCreator project from it. Use both.