解决 MSYS2 Qt 6.7 默认 stylesheet 在 windows 11 下的显示故障

项目场景：

MSYS2 升级到 Qt6.7.0，发现显示故障，所有Qt6程序以及 QtCreator的SpinBox都显示不全，Combox的底色不对。

问题描述

2024年4月1日，pacman升级MSYS2后，Qt6遇到风格错误。如果使用官方的 Qt online installer，则Qtcreator毫无问题（它使用6.6 而不是 6.7 编译），但是使用Qt 6.7 的app还是有问题。

msys环境：

user@worker UCRT64 ~
$ qmake6 --version
QMake version 3.1
Using Qt version 6.7.0 in C:/msys64/ucrt64/lib
Qt Creator 13.0.0

故障 windows环境：

$screenfetch
                                  ..,  guest@localhost
                      ....,,:;+ccllll  OS: Microsoft Windows 11 Home Edition (v10.0.22631) 64-bit
        ...,,+:;  cllllllllllllllllll  Kernel: x86_64 MINGW64_NT-10.0-22631 3.4.10.x86_64
  ,cclllllllllll  lllllllllllllllllll  Uptime: 503m
  llllllllllllll  lllllllllllllllllll  Packages: 1307
  llllllllllllll  lllllllllllllllllll  Shell: bash 5.2.26
  llllllllllllll  lllllllllllllllllll  Resolution: 1920x1080
  llllllllllllll  lllllllllllllllllll  DE: Modern UI/Metro
  llllllllllllll  lllllllllllllllllll  WM: DWM/Explorer
                                       WM Theme:Themesaero
  llllllllllllll  lllllllllllllllllll  CPU: Intel Core i7-10510U @ 8x 2.31GHz
  llllllllllllll  lllllllllllllllllll  GPU: Intel(R) UHD Graphics
  llllllllllllll  lllllllllllllllllll  RAM: 4172MiB / 24306MiB
  llllllllllllll  lllllllllllllllllll
  llllllllllllll  lllllllllllllllllll
  `'ccllllllllll  lllllllllllllllllll
         `'""*::  :ccllllllllllllllll
                        ````''"*::cll
                                   ``

错误图片:

上图的spinBox里的文字全部显示不全。

上图帮助系统中，ComboBox弹出的选项列表背景前景几乎一样，看不清

原因分析：

这个问题是错误的StyleSheet导致的。应该是Qt 6.7 的 windows 11风格没有在各种 DPI下进行严格的测试。鉴于官方的 Official Online Installer 对应的 Qt6.6的 qtcreator 没有问题，只能是 msys2 版本太高，提前暴露了Qt6.7某些配置至少在 mingw下有问题。

解决方案：

最简单的方法是用fusion主题或者其他主题启动 QtCreator:

$ qtcreator --style fusion

此问题应该很快会解决。