Please try the following. Click reply and then on the text box rightclick and click inspect. Does what you see look like the following image. Mine certainly didn’t when I woke up this morning, before a BSOD. Now the textbox is only 6 mm high and 35 mm wide, the topics on the left previously didn’t have bullets on them, even the title above was different.

What’s different about the data brought up by inspect?

eg. does 161 × 34 flash up above the text box? Are the parameters for text area the same?

I suspect that I need to manually edit the register to fix this.

I can drag bottom corner of text box to make it bigger (didn’t work first two times, third time lucky).
But still defaults to a tiny size.

On dragging, size marked on box lower right of image above changes, initially 157 × 30 (presumably points) get larger (to for instance 949 × 438 after dragging larger).

Font size for heading & left side bar still too big, and don’t want bulleting on left side bar.

Problem fixed, sorry to disturb.
I didn’t need to edit the register.

Just – settings: show advanced settings: click on “reset settings”.
Among other things this clears all cookies.

Then log in again to the forum as mollwollfumble with password.