Start with a new document in Draw. Insert a Layer as e.g. Layer 4 and switch to it.
Insert > Field, e.g. Time(variable).
Seen behavior: Field is on layer "Layout".
Expected behavior: Field is on the active layer "Layer 4".
Go to layer "Layout" and lock it.
Go to Insert > Field. Notice all options are disabled, what is correct.
Go to layer "Layer 4".
Go to Insert > Field > Page Number.
Seen behavior: The field is on layer "Layout", although that layer is locked. You cannot select it.
Expected behavior: Field is inserted on active layer "Layer 4".
Arch Linux 64-bit
Build ID: d357ea1d1ff95cb5ce2ee6b4828afa2484707256
CPU threads: 8; OS: Linux 4.18; UI render: default; VCL: gtk3_kde5;
Locale: fi-FI (fi_FI.UTF-8); Calc: threaded
Built on 28 September 2018