By the way, here is the patch (also fixes the related bug #896702)
---------------------
Alexander Kernozhitsky
diff -rU3 lazarus-1.8.4+dfsg.orig/debian/lcl-gtk2.install.in lazarus-1.8.4+dfsg/debian/lcl-gtk2.install.in
--- lazarus-1.8.4+dfsg.orig/debian/lcl-gtk2.install.in 2017-06-09 16:04:43.000000000 +0300
+++ lazarus-1.8.4+dfsg/debian/lcl-gtk2.install.in 2018-07-04 17:49:01.478017232 +0300
@@ -1,4 +1,5 @@
/usr/lib/lazarus/${VERSION}/components/ideintf/units/*/gtk2
+/usr/lib/lazarus/${VERSION}/components/lazcontrols/design/lib/*/gtk2
/usr/lib/lazarus/${VERSION}/components/lazcontrols/lib/*/gtk2
/usr/lib/lazarus/${VERSION}/components/synedit/design/units/*/gtk2
/usr/lib/lazarus/${VERSION}/components/synedit/units/*/gtk2
diff -rU3 lazarus-1.8.4+dfsg.orig/debian/lcl-qt5.install.in lazarus-1.8.4+dfsg/debian/lcl-qt5.install.in
--- lazarus-1.8.4+dfsg/debian/lcl-qt5.install.in 2017-10-21 08:22:18.000000000 +0300
+++ lazarus-1.8.4+dfsg/debian/lcl-qt5.install.in 2018-07-04 17:49:14.798023605 +0300
@@ -1,5 +1,6 @@
#! /usr/bin/dh-exec
/usr/lib/lazarus/${VERSION}/components/ideintf/units/*/qt5 [!linux-mips !linux-mipsel]
+/usr/lib/lazarus/${VERSION}/components/lazcontrols/design/lib/*/qt5 [!linux-mips !linux-mipsel]
/usr/lib/lazarus/${VERSION}/components/lazcontrols/lib/*/qt5 [!linux-mips !linux-mipsel]
/usr/lib/lazarus/${VERSION}/components/synedit/design/units/*/qt5 [!linux-mips !linux-mipsel]
/usr/lib/lazarus/${VERSION}/components/synedit/units/*/qt5 [!linux-mips !linux-mipsel]
diff -rU3 lazarus-1.8.4+dfsg.orig/debian/rules lazarus-1.8.4+dfsg/debian/rules
--- lazarus-1.8.4+dfsg/debian/rules 2018-05-24 10:30:04.000000000 +0300
+++ lazarus-1.8.4+dfsg/debian/rules 2018-07-04 17:48:48.202010921 +0300
@@ -212,12 +212,6 @@
find -name debian -prune -or '(' -name lib -or -name units ')' -print | xargs ${CP} --parents -t ${LIB_DIR}
# Remove READM.txt files from output directories
find ${LIB_DIR} '(' -name '*.or' -or -wholename '*/lib/README.txt' ')' -delete
- # Mark package as manually compilable and install them
- for package in `find -name '*.lpk'` ; \
- do \
- ${MKDIR} `dirname "${LIB_DIR}/$${package}"` ; \
- sed -e 's@\(\W*\)<CompilerOptions>.*@\1<AutoUpdate Value="Manually"/>\n&@' "$${package}" > "${LIB_DIR}/$${package}" ; \
- done
# Install packages global links
${CP} -t ${LIB_DIR}/packager $(CURDIR)/packager/globallinks
# copy icons and menu entries for the GNOME menu
