Dashboard & Expose windows switching problems

hello,

I recently reinstalled OSX 10.5.8 on a PPC DC 2Ghz mac, becuase my dashboard crashed and widgets stopped working.

After the installation, i re-added my widgets.

Then i went to System Preferences panel and set Expose to handle ALL WINDOWS with f9 or mouse button 4.

I opened photoshop cs4 and loaded 30images to edit.

I pressed f9 to see all the image windows. then hovered with mouse above each image to select one.

I left the mouse above one window and waited to switch to it.

Nothing happened. In the past after mouseover an window/frame in f9 mode was BLINKING/ flashing before switching to the selection automatically.

It should have blinked for a sec, then select the image window and go back to photoshop with the image window in the forground.

I also tried dragging a layer from 1 photoshop file to another one in the cascade/ stacked windows and still did not

select anything.

I also tried opening 5 folders on desktop, then f9 and try to select a folder and switch to it. nothing happened.

The windows stay arranged on the display but it does not switch to anyone, unless i click with left mouse button.

Is it dashboard problem or expose only ?

What do i have to do in order to bring this autoswitching functionality back please ?