In an empty presentation, click into a text box, and click away.
=> An undo step "Edit text of Text Frame..." is generated.
If the text box contains text, no undo step is generated.
Observed using LO 184.108.40.206.alpha1+ (26caf1bc59c81704f11225e3e431e412deb8c475) & 3.3.0 / Ubuntu 18.04.
Thank you for reporting the bug. I can not confirm the second step (If the text box contains text, no undo step is generated) in
Build ID: 86daf60bf00efa86ad547e59e09d6bb77c699acb
CPU threads: 2; OS: Windows 6.1; UI render: default;
Locale: en-US (en_US); Calc: group threaded
Arch Linux 64-bit
Build ID: c2d59ec2832c8b51568e73e9314ab9c82f1f5b7b
CPU threads: 8; OS: Linux 4.20; UI render: default; VCL: gtk3;
Locale: fi-FI (fi_FI.UTF-8); UI-Language: en-US
Built on 8 January 2019
Also on Win
Build ID: 6b4ea2d8ddd681fec98773d7e0bbec9657a1fc08
CPU threads: 4; OS: Windows 10.0; UI render: default; VCL: win;
Locale: fi-FI (fi_FI); UI-Language: en-US