To reproduce: - new impress - draw a CustomShape, keep it selected -> neither in context menu, nor in main menu is the slot for 'Text...' This is bad since that settings are imminent for text formatting in the sense of aligmnent. Especially since e.g. at pptx import, custom text shapes get created where you can no longer edit these alignments. In the same version in Impress that slot is available for own text shapes (insert Text Field, F2). In the same version in Draw that slot is available for CustomShapes in main menu Format/Text... In the same version in Writer that slot is available for CustomShapes in main menu and context menu. In the same version in Calc that slot is available for CustomShapes in main menu and context menu.
Confirmed in few days old master build It is clearly a bug that the slot ain't available anywhere in Impress. It can be discussed whether it should be also available via context menu (I'd vote for 'yes'), but it should be at least made consistent across apps -- so either add the entry for Impress and Draw, or remove it from Calc and Writer and have it accessible only via Format menu
In LO 5.2 I see it very inconsistent: Writer selected context menu > Text… Format > Text Box and Shape > Text Attributes Writer edit mode Format > Text Box and Shape > Text Attributes Calc selected contect menu > Text… Format > Object > Text… Calc edit mode contect menu > Text… Format > Object > Text… Draw selected Format > Text… Draw edit mode contect menu > Text… Format > Text… Impress selected Format > Object > Text… Impress edit mode contect menu > Text… Format > Object > Text… I prefer to have it in context menu.
I believe this is a duplicate of bug 94448. Regarding consistency, i've been plugging away at that little by little, including in a recent patch. https://gerrit.libreoffice.org/#/c/20640/
*** This bug has been marked as a duplicate of bug 94448 ***