Whenever KDE starts up the panel items on the top panel are rearranged. Even if I lock the widgets, the clock and system tray still move to the left instead of staying to the right. I usually remove the panel shadow on the top panel. The widgets that are on the top panel include: Digital Clock, System Tray, Active Window Control, and Global Menu. If it helps I have Active Window Control set to remove the window border when it is maximized and also dynamically change size. I do not have any bug information for this because KDE does not seem to recognize this as a bug. I am running KDE Manjaro which is Arch-based. I am running Manjaro from the stable branch.