Using the "insert formula" button on the "Insert" toolbar causes the toolbar to
close permanently, whereas the other functions on the same toolbar do not.

Steps to reproduce:

1. File > New > Text Document
2. View > Toolbars > Insert
   * A floating toolbar will appear
3. Click the "Formula" button (icon shows square root symbol)
   * The formula editor will start, and the Insert toolbar will close
4. Leave the formula editor by clicking in the parent document
   * The Insert toolbar does not re-appear
   * The "Insert" item under View > Toolbars is now un-checked

Expected behavior:

The Insert toolbar should re-appear after the formula is inserted.

None of the other buttons on the same toolbar cause it to close.

If the button with the same function (i.e. "Insert formula object") is added to
other toolbars, it functions as expected.

If a formula text (e.g. "a over b") is typed in the text document and selected,
THEN the formula button is clicked, the selected text is converted into a
formula and the Insert toolbar remains open.

This problem affects both toolbars where the "Insert formula object" appears in
the default configuration:

 Writer, Writer/Web, Draw, Impress: toolbar labeled "Insert"

 Calc: toobar labeled "Insert Object"

Observed on Windows and Linux.