Open Writer. You should see the Formatting toolbar. Enable the "Insert Formula" icon in the Standard toolbar, in case you have not done yet. Write a text, which can be a formula. For example write a^2+b^2=c^2. Mark this text and click on "Insert Formula". The text should be converted to a Math object without opening the UI of Math. Click in text to leave object mode. Notice, that this action has closed the Formatting toolbar and it does not open again. That should not happen and did not happen in older Versions. Go to menu View > Toolbars and try to reopen the Formatting toolbar. It is not possible. To repair the state of LibreOffice double click the formula to open the Math UI, click into the Writer text to leave the Math UI, and click again into the Writer text. Now the Formatting toolbar should be open again. Otherwise restart LibreOffice. I use version 5.4 on Windows 7. Converting to Math this way works in version 5.2.
Confirmed On Windows build with STR as given. the Formatting toolbar returns in Version: 5.4.0.0.alpha0+ Build ID: cb598029835477326b190bc99abd31a487cc5a91 CPU Threads: 8; OS Version: Windows 6.19; UI Render: GL; TinderBox: Win-x86@39, Branch:master, Time: 2016-12-09_00:51:51 Locale: en-US (en_US); Calc: C but goes missing, on return from OLE math object, with Version: 5.4.0.0.alpha0+ Build ID: b894104a0b02a9b074c76feb925389d7bee6a493 CPU Threads: 8; OS Version: Windows 6.19; UI Render: GL; TinderBox: Win-x86@39, Branch:master, Time: 2016-12-10_01:00:52 Locale: en-US (en_US); Calc: CL https://cgit.freedesktop.org/libreoffice/core/log/?qt=range&q=cb598029835477326b190bc99abd31a487cc5a91..b894104a0b02a9b074c76feb925389d7bee6a493 This looks kind of suspect... https://cgit.freedesktop.org/libreoffice/core/commit/?id=84f2ff67a7e404febf710b1dc7f66d06745c503f
oops, sorry about that, was caused by poor reading comprehension on my part. regression from: commit 84f2ff67a7e404febf710b1dc7f66d06745c503f Author: Michael Stahl <mstahl@redhat.com> AuthorDate: Fri Dec 9 23:42:14 2016 +0100 framework: fix race in ToolBarManager creation fixed on master
Michael Stahl committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=d266cb32c3c982a60cd68650dd7ae8983744134e tdf#104621 framework: Redo commit 84f2ff67a7e404febf710b1dc7f66d06745c503f It will be available in 5.4.0. The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
This only affected a brief set of 5.4.0.0alpha0+ builds of master in Dec 2016, n/a to 5.3 no backport needed. Verified it does not affect current 5.3 releases Version: 5.3.1.2 (x64) Build ID: e80a0e0fd1875e1696614d24c32df0f95f03deb2