Just like for tables (see bug 148675), frames (and the default Frame style "Frame") should use Automatic instead of Black as a default border colour, so the frame remains visible when using a dark scheme in Application Colors. Steps: 1. Use Tools > Options > LibreOffice > Application Colors > Custom Colors > Automatic: Dark 2. Insert > Frame > Frame interactively Result: the border is black on dark background. If Formatting Marks is off, it's very hard to spot the frame (especially since text boundary is not shown by default now, see bug 131253). Version: 24.8.0.0.alpha1+ (X86_64) / LibreOffice Community Build ID: 1f15d097cace14ca6e44e7652f460aa3fa7bd150 CPU threads: 8; OS: Linux 6.5; UI render: default; VCL: gtk3 Locale: en-AU (en_AU.UTF-8); UI: en-US Calc: CL threaded Already the case in OOo 3.3.
I confirm it with Version: 24.8.0.0.alpha1+ (X86_64) / LibreOffice Community Build ID: d2eab48f697a1e6097778158f623f11306ac7a3d CPU threads: 4; OS: Windows 10 X86_64 (10.0 build 19045); UI render: Skia/Raster; VCL: win Locale: de-DE (de_DE); UI: en-GB Calc: CL threaded => NEW But as Rafael statet in bug 148675 comment 2 "border colors do not have an "Automatic" color option, so I'm not sure how we will be able to handle dark borders in Dark mode." I couldn't find an answer to that question in bug 148675.