#92 Subsong slider not automatically updated

[Anonymous]

When File Info dialogue box is open but inactive, loading songs with different number of subsongs does not cause the dashes under the Subsong slider and the slider position to be updated until the File Info dialogue box becomes active, even though other song data within the inactive dialogue (including number of subsongs, current subsong number) are updated when loading different songs. For samples with different number of subsongs, see attachment in bug 3078281.