Mouse control in JOSM

I´m new to JOSM, but have succeeded in making a few edits. However, I find it difficult to control the mouse. With tiny movements of the finger the imagery zoom in and out, sometimes seeing onlly a multicoloured blob.
Any commands to set the zoom level in JOSM?
I´m using an Apple cordless mouse and I don´t have any problems using other software (or the editor ID).
Hope someone out there have some tricks.

The same problem occurs for me when josm slows and I apply too much zoom out.
Luckily I discovered that the short cut ‘8’ goes to the previous view.

Thanks nevw, shortcut ´8´helps me to not get completely lost. Any more tricks, anyone?
The cmd + and cmd - do not work, so in that case I have to use the menu button.

In Windows10 the + and - can be used to zoom