我正在尝试运行wmsystemtray命令但它输出：
wmsystemtray: Another application is already running as the freedesktop.org protocol system tray
wmsystemtray: Could not initialize the freedesktop.org tray protocol
所以我想查看所有使用此协议的进程/命令。怎么做？
桌面环境：KDE。操作系统：Linux Mint 18。
重启之前PSwmsystemtray已经启动成功。