Why did my grid go?

My grid disappeared.

I tried deleting querymemoheight in the registry with no effect.

Any help would be appreciated.

Tools->Reset panel dimensions.

Got it.

HeidiSQL should sense when there is a problem and adjust the panel automatically.

The editor in your screen is too high and goes beyond the lower log panel.

Earlier versions had a logic which reduced the editor height when the log panel got more height, and vice versa, in order to keep the grid area visible. The involved splitters were also set to disallow a minimum size besides them. Many events triggered that resizing (plus my own logic), and some of them lead to endless loops. Quite complex stuff, although that might not seem so!

Might be worth to give it a new attempt. But for the moment that "Reset panel dimensions" is the manual way to fix the invisible grid.