I'm using ubuntu with xfce, and today a strange problem appeared: the "keyboard cursor" (the blinking vertical line showing the place where your typing will appear in text) has completely disappeared. This happens in Libreoffice writer and abiword, but the cursor is still seen in text boxes in web, search box, in renaming files etc. The cursor can also seen when editing source files in Rstudio. I can still write the text but have to guess where it appears which is obviously making it virtually impossible to edit a document of any reasonable length.
Thanks in advance for any suggestions.