Start a presentation, switch to Master view via View -> Slide Master, click into a text box, and paste text into it. => It's possible to paste text into a master slide. Normal editing is disallowed, the placeholder entries can only be formatted, thus pasting shouldn't be allowed, either. Observed using LO 7.2.0.0.alpha0+ (2577d9ecea199ca2c10d852cf279053a1b22faf7), 5.3.0.3 / Ubuntu. In earlier versions Impress crashes for me when I switch to Master view.
Hello Aron, Thank you for reporting the bug. I can confirm that the bug is present in master. Version: 7.6.0.0.alpha0+ (X86_64) / LibreOffice Community Build ID: fb3a6b82b55a298eabf8f431f1451dc826642acd CPU threads: 4; OS: Windows 10.0 Build 19045; UI render: Skia/Raster; VCL: win Locale: fr-FR (fr_FR); UI: fr-FR Calc: CL threaded