add to selection mode (shift+F8) disabled after moving more than 1 cell away

hi,

I have a problem with my add-to-selection mode (Shift+F8)

• Selected multiple rows and columns
• Pressed Shift+F8
• Status bar: Ready - Add to selection
• Pressed the arrow key once (regardless of direction)
• Status bar: Ready
• Pressed the arrow key again
• Cells deselected

Funny enough, this problem doesn't happen in protective mode (editing mode disabled)

Please help!