Learn English – Use of ‘ing’ after to

I am a developer working on Microsoft technologies.

This sounds like you are working for Microsoft on their new technologies. If that's true, then you should state what the technologies are.

I am a developer working in Microsoft technologies.

This sounds like you are working for a division of Microsoft called "technologies".

I am a developer working with Microsoft technologies.

This sounds like what you are really after: you develop using Microsoft technologies.

Perhaps a better way to say this would be:

I develop web applications using Microsoft C# and WCF.

... or whatever the real application area and technologies are.

I'd say 'That's typical of him' would be far more common than the alternative.

However, in 'This meal is typical of local cookery', 'is typical of' can be replaced by 'is a typical example of'.

While in 'This meal is typical for the area', 'is typical for' can be replaced by 'is representative of what can be found [produced] in/by'.

Usage does seem rather unpredictable. Perhaps 'That's [just] typical of him' should be regarded as an idiomatic usage, and the two substitution-tests above taken as a rule of thumb.