LibreOffice 126.96.36.199 in i3 on Slackware current - when selecting color picker for fonts and highlighting in Writer, Calc, Impress, Base, and Draw (line color selection but not area color - that drop down menu works OK) a floating menu window opens which immediately closes. In i3 config I set libreoffice as default floating and problem persists. In KDE 5 on the same Slackware install there is not this problem. I cannot provide a screenshot as it happens very quickly.
*** This bug has been marked as a duplicate of bug 90155 ***