grey blank space on the left side in excel

[yoyoyojohnny]

Hi,
I have a toggle button in excel performing a big macro.
Whenever I unpress-press that button i get a grey blank space on the left side in the excell shell.
Please note: this is in the shell only: if I click on the restore button (between the close and minimize buttons) on the top left side of the excel shell, I am able to adjust the windows of the excel files open in the shell. That means that when I get the blank space I just enlarge the excel shell window and move my windows with the files to the right ans thus I am able to see the stuff in those windows.
I tried to restart excel, restart the computer, but anyway it does not help: I still get the blank space on the left side. Its width is the same as the width of the space with recovered files (that are saved when I close excel using Task Manager) that comes up when I reopen excel... Maybe this is the problem? But I disabled the auto recover function hoping that this will solve the problem... Still no luck.

Could anyone please suggest what to do?

 

[yoyoyojohnny]

1. Sorry, I meant top Right side of the excel window

2. the macro does not take a lot of memory: I checked it with the Task Manager, so I don't think it's a memory problem