Comment 4 for bug 1157289

I can confirm this is happening with a pretty stock Kubuntu setup. I can also give a work-around:

Close all zim processes (including the trayicon if you have that enabled), and run:

GDK_NATIVE_WINDOWS=1 zim

As a really goofy quick fix, you can also right click to bring up the context menu, which will also make the pointer reappear.

As a pure guess, the text widget is turning off the mouse pointer when somebody starts typing (a common editor practice), but not turning it back on when the mouse is moved. As a result, this is a very reliable bug: move the mouse into the text space, type a character to make the pointer disappear, then it works *outside* the text space, but is invisible over the text. To make reappear, right click in the text space and it reappears until another key is pressed.

Using the GDK_NATIVE_WINDOWS work-around, the expected behavior occurs: the mouse pointer disappears when a key is pressed, but then reappears as soon as the mouse is moved.

I use the term "text space" because I'm not sure where the boundaries of the effect are, and I'm trying not to make assumptions in a bug report.

Much respect and thanks to all the devs,
Evan 'JabberWokky' Edwards