How to drag the page up

[faint egret]

When using a tablet I sometimes need to scroll up to look at the lines, history etc below the board. You obviously can't drag the a square with a piece on it as you'll move the piece instead of scrolling. But a number of the squares don't let me drag either - I'm just ignored. Can someone explain how I know which squares I can use? If there's a pattern to it I can't figure it out. Feature request - allow the user to use any empty square to drag, as expected.
Example: I can't drag using E6, but I can with E7. This is on multiple devices running chrome.

[silver berry]

Any empty square should work but it's blocked when it's close to a piece to avoid accidentally scrolling when you just missed a piece.

So larger empty areas are best

Or elements outside of the boards e.g. the analysis top bar

[faint egret]

There's nothing above the board in my use case - i've scrolled it to the top. Nor to the sides. I'm in analysis mode so there'd be no problem were I to accidentally move a piece. But I guess now I know of the issue I'll just always use the line below the board with the eval/stockfish version number/engine toggle.