The dialog was using a LIB_ALIAS from library cache to show the symbol to the canvas without making a local copy.
Unfortunately, the library viewer is doing the same thing.
Now the GAL is used in Eeschema, a link to the VIEW used by the GAL canvas is stored in this class.
When The selector symbol dialog is used to choose a symbol to display in the Library viewer,
a race condition between the Library viewer GAL canvas and the dtor dialog that destroyed this link in the same instancied class.
Now, the SYMBOL_PREVIEW_WIDGET used in the dialog works on a local copy of the symbol to display.
Split antialiasing options out from display options. Move
antialiasing to common. Duplicate the rest of display options
for Eeschema.
Implement OnSelectGrid and hookup GAL canvas refresh to
SetPresetGrid.
Add Grid Settings... to View menu and move Show Grid from
preferences to View Menu to match Pcbnew.
jean-pierre charras
Jeff Young