We sometimes hear from Mac users that they are having issues with scrolling in simulations and we're working on coming up with a resolution for you - but, in the meantime, we have a couple suggestions that have worked for other Mac users:
First, try placing your cursor over the Tools Panel and scrolling down using your device's scroll function - for a touchpad, this would be a Mac "2-finger tap-&-drag".
If that doesn't work, press and hold the CTRL key and click the "-" (the minus key on the upper-right of your keyboard) to zoom out. As you continue to zoom out by continuing to click "-" (don't forget to hold the CTRL key), your screen will be redrawn for you and you'll eventually see all the tools on one screen. From here, you can select your preferred tool. (To zoom back out to your preferred view once you've selected your tool, simply hold CTRL and use "+" key.)
Hopefully one of these tips will resolve your issue, but please let us know if you need additional assistance.