You rarely change the width of Visual Studio toolbar elements, but it is good to know about such possibility. For example, to change the width of Solution Configurations drop-down list, go to toolbar customization and adjust the Width value:
Toolbar element width customization in Visual Studio 2013
References:
http://social.msdn.microsoft.com/Forums/vstudio/en-US/7b6a504c-7df0-40b3-900f-4ff49a7b0f95/how-to-change-the-width-of-solution-configurations-dropdown-list-in-the-ide-toolbar?forum=vsx
http://mikesknowledgebase.azurewebsites.net/pages/Other/VS2012ConfigurationToolbar.htm
Making Visual Studio perfect 
This does not work for VS2017 anymore
I’ve just tried it with VS 2017 v15.8.4 and it works as usual.
Thx, still works with VS2017
This still works for VS2019, thank you! 🙂