Spotfire Client: Bookmarks with filtered to columns become invalid

When using "Marked Rows > Filter to" and bookmarks, for example:

1. Mark some data in the visualization and click "Marked Rows > Filter to" from the visualization. 

   This creates the special filter (Mask column) in Spotfire called, "Filtered to at <timestamp>".

2. Create a bookmark - "Bookmark1".
3. Repeat step 1, at which point the mask column "Filtered to at <timestamp>" updates to the new timestamp value.
4. This will break the bookmark "Bookmark1" that was created in step 2 since the mask column no longer exists.

When applying the bookmark, a message is displayed like:

The following issues were detected when applying bookmark 'bookmark1'
The column 'Filtered to at 2:09:17 PM' does not exist. Filter settings cannot be applied for the missing column.
The marking 'Marking' for data table 'BASEBALL' cannot be applied. Columns or rows may have been added or deleted without key columns defined.

When you 'Filter To' on marked rows, a temporary column is created of type 'Mask'.

Mask - a temporary column created using the Edit > Marked Rows > Filter To command. This command creates a column with information of whether or not a column was filtered to, the last time the command was applied. There can only be one mask column in each data table.

Bookmarks are designed to remember everything, including temporary columns. Since the mask columns are temporary and will be replaced when the "filter to" changes, the bookmark will complain about missing column.

To resolve the issue, delete the "mask" column before creating a bookmark.