Topic: hit area on custom arrows?

I made my custom arrows and moved them to a desired position,
but there seems to be a problem with computing the hit area. Since I have only one column of thumbs (and even that is reduced to size 35pix) the two arrows are fairly close to each other and the back arrow seems to "steal" the mouse clicks which should be processed by the next arrow. Where should I look to fix this?

Many thanks,

Re: hit area on custom arrows?

Anybody has an idea?