[Reg 6.7.0 -> 6.7.1] Slowness of some languages / changing languages

Our relatively complex QML desktop application was recently changed to use MSVC compiler on Windows. While functionality remains ok, changing language in the application for example between Japanese and western languages became much slower the first time. For some reason, consecutive changes are much faster. Anyway, startup of the app with western language may be slower too but it is less noticeable there.

Not sure if it is related but I made a simple test app that has a simple toggle-button to switch between English and Japanese translations and a long list of translated indexes in the UI.

While in English, it is relatively fast to see the toggle button hovering changes - or to resize the window. But when in Japanese, hovering the button and resizing window are much slower. These are on Windows & MSVC compiler. In Linux this does not seem to be a problem. In this case, the actual changing of the language is slow on both platforms, so possibly it is a different issue on a real application with much more complex layout.

In test app it is possible to modify the amount of indexes in the source code to make the issue more visible. Not sure if related or not but in some other code of ours I had to change the default algorithm of std::search to use std::boyer_moore_searcher to make it faster than the default on MSVC.