The toolbar buttons for promote and demote have arrows pointing due left (promote) and due right (demote) - indicating the direction in which the action is likely to move the paragraph text due to changes in indentation. In Writer, these toolbar buttons have their icons flipped when the paragraph direction is RTL. But in Impress - they do not. Not sure why this wasn't fixed in both modules at once.
Created attachment 186374 [details] Impress window with promote/demote on main toolbar and RTL bulleted paragraph Note the bright blue rightwards arrow button on the top toolbar. The paragraph cannot go any further to the right, only due left. So, only the demote button is enabled :-(
Reproduced with the latest LO 7.5 dev master: Version: 7.6.0.0.alpha0+ (X86_64) / LibreOffice Community Build ID: 8c3e219a831719ebb40dd2af8a26b0a24ad7aba1 CPU threads: 12; OS: Linux 5.19; UI render: default; VCL: gtk3 Locale: en-US (en_US.UTF-8); UI: en-US Calc: CL threaded Note that in different icon themes, the icons are different but the problem of the direction of the arrows is still visible. In "Elementary" icon theme, the problem is better visible as it only uses simple arrows.